Month: November 2012

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Plastic relocation of motor cortex in a patient with LGG (low grade glioma) confirmed by NBS (navigated brain stimulation)

Acta Neurochir (2012) 154:2003–2008

We report on a patient with LGG, in whom NBS mapping confirmed relocation of the primary motor cortex (M1) concurrent with multistage surgery. Comparing the NBS results at 18 months with the initial results revealed that the M1 representation had shifted from the precentral to the postcentral gyrus. The patient underwent a third surgical intervention. Intraoperative direct cortical stimulation (DCS) confirmed the shift of the M1. Plastic changes in M1 localization permitted complete tumour removal without neurological sequela. To our knowledge, this is the first report on a LGG patient where induced brain plasticity has been confirmed by NBS mapping.

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Meningiomas in Pregnancy

Neurosurgery 71:951–961, 2012

Dramatic growth of meningiomas is occasionally encountered during pregnancy. While cell proliferation is often assumed, hemodynamic changes have also been touted as a cause.

OBJECTIVE: We identified 17 meningiomas resected during pregnancy or within 3 weeks post-partum and characterized them to determine the cause of occasional rapid growth in pregnancy.

METHODS: Seventeen tumors were identified from searches at 4 university centers. All available clinical records, radiology images, and tissue specimens were reviewed, with immunohistochemical studies performed as needed.

RESULTS: Sixteen patients underwent tumor resection and 1 died of complications prior to surgery. Average patient age was 32 years. Nine experienced onset of symptoms in the third trimester or within 8 days post-partum. Principle physical findings included visual complaints (59%) and cranial nerve palsies (29%). Ten tumors (59%) were located in the skull base region. The Ki-67 labeling index was low (0.5-3.6%) in 11 of 13 benign (grade I) tumors and elevated (11-23.2%) in 3 of 4 atypical (grade II) meningiomas. Eight (50%) tumors featured hypervascularity with at least focal CD34- positive hemangioma-like microvasculature. Fourteen (82%) showed evidence of intraand/ or extracellular edema, 1 so extensive that its meningothelial nature was not apparent. Five tumors (29%) exhibited intratumoral hemorrhage and/or necrosis.

CONCLUSION: Our series suggests that pregnancy-associated meningiomas located in the skull base are likely to require surgical intervention for visual complaints and cranial nerve palsies. The rapid tumor growth is more often due to potentially reversible hemodynamic changes rather than hormone-induced cellular proliferation.

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The impact of brain shift in deep brain stimulation surgery

Acta Neurochir (2012) 154:2063–2068

The impact of brain shift on deep brain stimulation surgery is considerable. In DBS surgery, brain shift is mainly caused by CSF loss. CSF loss can be estimated by post-surgical intracranial air. Different approaches and techniques exist to minimize CSF loss and hence brain shift. The aim of this survey was to investigate the extent and dynamics of CSF loss during DBS surgery, analyze its impact on final electrode position, and describe a simple and inexpensive method of burr hole closure.

Methods Sixty-six patients being treated with deep brain stimulation were retrospectively analyzed for this treatise. During surgery, CSF loss was minimized using bone wax as a burr hole closure. Intracranial air volume was calculated based on early post-surgery stereotactic 3D CT and correlated with duration of surgery and electrode deviations derived from post-surgery image fusion.

Results Median early post-surgery intracranial air was 2.1 cm3 (range 0–35.7 cm3, SD 8.53 cm3). No correlation was found between duration of surgery and CSF-loss (R0 0.078, p00.534), indicating that CSF loss mainly occurs early during surgery. Linear regression analysis revealed no significant correlations regarding volume of intracranial air and electrode displacement in any of the three principal axes. No significant difference regarding electrode deviations between first and second side of surgery were observed.

Conclusions CSF loss mainly occurs during the early phase of DBS surgery. CSF loss during a later phase of surgery can be effectively averted by burr hole closure. Postoperative intracranial air volumes up to 35 cm3 did not result in significant electrode displacement in our series. Comparing our results to studies previously published on this subject, burr hole closure using bone wax is highly effective.

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Short circuit in deep brain stimulation

J Neurosurg 117:955–961, 2012

The authors undertook this study to investigate the incidence, cause, and clinical influence of short circuits in patients treated with deep brain stimulation (DBS).

Methods. After the incidental identification of a short circuit during routine follow-up, the authors initiated a policy at their institution of routinely evaluating both therapeutic impedance and system impendence at every outpatient DBS follow-up visit, irrespective of the presence of symptoms suggesting possible system malfunction. This study represents a report of their findings after 1 year of this policy.

Results. Implanted DBS leads exhibiting short circuits were identified in 7 patients (8.9% of the patients seen for outpatient follow-up examinations during the 12-month study period). The mean duration from DBS lead implantation to the discovery of the short circuit was 64.7 months. The symptoms revealing short circuits included the wearing off of therapeutic effect, apraxia of eyelid opening, or dysarthria in 6 patients with Parkinson disease (PD), and dystonia deterioration in 1 patient with generalized dystonia. All DBS leads with short circuits had been anchored to the cranium using titanium miniplates. Altering electrode settings resulted in clinical improvement in the 2 PD cases in which patients had specific symptoms of short circuits (2.5%) but not in the other 4 cases. The patient with dystonia underwent repositioning and replacement of a lead because the previous lead was located too anteriorly, but did not experience symptom improvement.

Conclusions. In contrast to the sudden loss of clinical efficacy of DBS caused by an open circuit, short circuits may arise due to a gradual decrease in impedance, causing the insidious development of neurological symptoms via limited or extended potential fields as well as shortened battery longevity. The incidence of short circuits in DBS may be higher than previously thought, especially in cases in which DBS leads are anchored with miniplates. The circuit impedance of DBS should be routinely checked, even after a long history of DBS therapy, especially in cases of miniplate anchoring.

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Comparison of Indocyanine Green Angiography and Laser Speckle Contrast Imaging for the Assessment of Vasculature Perfusion

Neurosurgery 71:1023–1031, 2012

Assessment of the vasculature is critical for overall success in cranial vascular neurological surgery procedures. Although several methods of monitoring cortical perfusion intraoperatively are available, not all are appropriate or convenient in a surgical environment. Recently, 2 optical methods of care have emerged that are able to obtain high spatial resolution images with easily implemented instrumentation: indocyanine green (ICG) angiography and laser speckle contrast imaging (LSCI).

OBJECTIVE: To evaluate the usefulness of ICG and LSCI in measuring vessel perfusion.

METHODS: An experimental setup was developed that simultaneously collects measurements of ICG fluorescence and LSCI in a rodent model. A 785-nm laser diode was used for both excitation of the ICG dye and the LSCI illumination. A photothrombotic clot model was used to occlude specific vessels within the field of view to enable comparison of the 2 methods for monitoring vessel perfusion.

RESULTS: The induced blood flow change demonstrated that ICG is an excellent method for visualizing the volume and type of vessel at a single point in time; however, it is not always an accurate representation of blood flow. In contrast, LSCI provides a continuous and accurate measurement of blood flow changes without the need of an external contrast agent.

CONCLUSION: These 2 methods should be used together to obtain a complete understanding of tissue perfusion.

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Normalization of hindbrain morphology after decompression of Chiari malformation Type I

J Neurosurg 117:942–946, 2012

Chiari malformation Type I (CM-I) is characterized by hindbrain deformity. We investigated the effects of craniocervical decompression surgery on the anatomical features of hindbrain deformity with a prospective MRI study of patients with CM-I.

Methods. A prospective longitudinal study was conducted in 48 patients with CM-I (39 with syringomyelia) treated with craniocervical decompression. Clinical examinations and cervical MRI were performed before surgery and 1 week, 3–6 months, and annually after surgery. Hindbrain deformity was defined by tonsillar ectopia, pointed cerebellar tonsils, and/or cervicomedullary protuberance. The length of the clivus, basiocciput (sphenooccipital synchondrosis to basion), supraocciput (internal occipital protuberance to opisthion), and anteroposterior (AP) width of CSF pathways at the foramen magnum were measured and compared with those from 18 healthy volunteers (control group).

Results. Before surgery, the patients’ posterior fossa bones were short and their CSF pathways were narrow. All patients had tonsillar ectopia (mean [± SD] 12.3 ± 5.1 mm; normal 0.3 ± 1.0). The majority of patients had pointed tonsils and more than two-thirds exhibited a cervicomedullary protuberance. Clivus and basiocciput lengths were significantly shorter than the values obtained in the control group. However, the supraocciput length did not differ significantly from control measurements. The mean bulbopontine sulcus distance superior to the basion was 9.5 ± 2.6 mm (vs 13.6 ± 2.8 mm in controls; p < 0.0001). The AP widths of the CSF pathways at the level of the foramen magnum were significantly narrowed. After surgery, CSF pathways significantly expanded both ventrally and dorsally. By 3–6 months after surgery, pointed tonsils became round, cervicomedullary protuberance disappeared, and tonsillar ectopia diminished by 51% (to 6.0 ± 3.3 mm; p < 0.0001).

Conclusions. The cerebellar tonsils and brainstem assumed a normal appearance within 6 months after craniocervical decompression. These findings support the concept that the CM-I is not a congenital malformation of the neural elements but rather an acquired malformation that arises from pulsatile impaction of the cerebellar tonsils into the foramen magnum.

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Extent of resection in glioblastoma

J Neurosurg 117:851–859, 2012

The extent of resection (EOR) is a known prognostic factor in patients with glioblastoma. However, gross-total resection (GTR) is not always achieved. Understanding the factors that prevent GTR is helpful in surgical planning and when counseling patients. The goal of this study was to identify demographic, tumor-related, and technical factors that influence EOR and to define the relationship between the surgeon’s impression of EOR and radiographically determined EOR.

Methods. The authors performed a retrospective review of the electronic medical records to identify all patients who underwent craniotomy for glioblastoma resection between 2006 and 2009 and who had both preoperative and postoperative MRI studies. Forty-six patients were identified and were included in the study. Image analysis software (FIJI) was used to perform volumetric analysis of tumor size and EOR based on preoperative and postoperative MRI. Using multivariate analysis, the authors assessed factors associated with EOR and residual tumor volume. Perception of resectability was described using bivariate statistics, and survival was described using the log-rank test and Kaplan-Meier curves.

Results. The EOR was less for tumors in eloquent areas (p = 0.014) and those touching ventricles (p = 0.031). Left parietal tumors had significantly greater residual volume (p = 0.042). The average EOR was 91.0% in this series. There was MRI-demonstrable residual tumor in 69.6% of cases (16 of 23) in which GTR was perceived by the surgeon. Expert reviewers agreed that GTR could be safely achieved in 37.0% of patients (17 of 46) in this series. Among patients with safely resectable tumors, radiographically complete resection was achieved in 23.5% of patients (4 of 17). An EOR greater than 90% was associated with a significantly greater 1-year survival (76.5%) than an EOR less than 90% (p = 0.005).

Conclusions. The authors’ findings confirm that tumor location affects EOR and suggest that EOR may also be influenced by the surgeon’s ability to judge the presence of residual tumor during surgery. The surgeon’s ability to judge completeness of resection during surgery is commonly inaccurate. The authors’ study confirms the impact of EOR on 1-year survival.

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Cognitive functioning early after surgery of gliomas in eloquent areas

J Neurosurg 117:831–838, 2012

Patients with gliomas frequently have cognitive deficits, and surgery can exacerbate these deficits. Preoperative assessment is therefore crucial in patients undergoing surgery for glioma in eloquent areas, because the proximity of functional areas increases the risk of permanent postoperative cognitive disturbances. Although pre- and postoperative language and motor function in patients with glioma have been investigated frequently, data on good cognition studies are scarce. Most studies have focused on clinical neurological functioning or have only used brief neurological instruments. The authors investigated whether surgery for glioma in eloquent areas influences cognition early after surgery, by using an elaborate test protocol.

Methods. Twenty-eight patients with gliomas of the left hemisphere in language and nonlanguage areas were assessed before and 3 months after surgery with a comprehensive neuropsychological test protocol. The authors performed a correlation analysis between change in cognitive performance and tumor characteristics (that is, location, volume, pathological features, and histological grade) and between cognitive change and treatment-related factors (the extent of the resection and postoperative treatment with chemo- and radiotherapy).

Results. Both pre- and postoperatively, the mean performance of the patients was worse than the performance of the normal population in the language domain, the memory domain, and the executive functions (p < 0.05). Postoperatively, a decline was found in the language domain (t = 2.34, p = 0.027) and in the executive functions (t = 2.45, p = 0.022). However, cognitive change postsurgery was influenced by the location of the tumor; the decrease of cognitive score in the language domain was only observed in patients with tumors in or close to language areas (t = 2.33, p = 0.029). No effect on cognitive change was found for the other tumor characteristics and treatment-related factors.

Conclusions. This study underlines the importance of the use of a neuropsychological test protocol before and after surgery in patients with glioma, because several tasks in the domains of language, memory, and executive functions appeared to deteriorate after surgery. Tumor resection in language areas increases the risk of cognitive deficits in the language domain postoperatively.

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Pituitary Centers of Excellence

Neurosurgery 71:916–926, 2012

Pituitary tumors and associated neuroendocrine disorders pose significant challenges in diagnostic and therapeutic management. Optimal care of the “pituitary patient” is best provided in a multidisciplinary collaborative environment that includes not only experienced pituitary practitioners in neurosurgery and endocrinology, but also in otorhinolaryngological surgery, radiation oncology, medical oncology, neuro-ophthalmology, diagnostic and interventional neuroradiology, and neuropathology.

We provide the background and rationale for recognizing pituitary centers of excellence and suggest a voluntary verification process, similar to that used by the American College of Surgeons for Trauma Center verification. We propose that pituitary centers of excellence should fulfill 3 key missions: (1) provide comprehensive care and support to patients with pituitary disorders; (2) provide residency training, fellowship training, and/or continuing medical education in the management of pituitary and neuroendocrine disease; and (3) contribute to research in pituitary disorders.

As this is a preliminary proposal, we recognize several issues that warrant further consideration including center and surgeon practice volume as well as oversight of the verification process.

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Assessing the functional status of the motor system in brain tumor patients using transcranial magnetic stimulation

Acta Neurochir (2012) 154:2075–2081

Transcranial magnetic stimulation (TMS) is being used in the pre-operative diagnostics of patients with tumors in or near the motor cortex. Although the main purpose of TMS in such patients is to map the functional areas of the motor cortex in spatial relation to the tumor, TMS also provides some numerical neurophysiological measurements of the functional status of the patient’s motor system. The aim of this paper is to provide reference values for these neurophysiological measurements from a large and varied clinical sample.

Methods TMS was used in the pre-operative work-up of patients with various types of tumors in or near the motor cortex during a 3-year period. Data was collected prospectively in 100 patients, yet this is a post hoc report.

Results Patient characteristics had no influence on the neurophysiological parameters. The response latency time was almost never different in the tumorous versus healthy hemisphere, so clinicians should be suspicious if they find interhemispheric differences for latency. A high interhemispheric ratio of resting motor threshold (RMT) or a low interhemispheric ratio of motor evoked potential (MEP) amplitude appear to suggest immanent deterioration of the patient’s motor status.

Conclusion In addition to topographic cortical mapping, TMS also serves as a neurophysiological assessment of the functional status of the patient’s motor system. The results presented here provide clinicians with a set of reference values to contextualize findings in their own tumor patients. Further research is still needed to better understand the full clinical relevance of these neurophysiological parameters.

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Differences in simple morphological variables in ruptured and unruptured middle cerebral artery aneurysms

J Neurosurg 117:913–919, 2012

Management of unruptured intracranial aneurysms remains controversial in neurosurgery. The contribution of morphological parameters has not been included in the treatment paradigm in a systematic manner or for any particular aneurysm location. The authors present a large sample of middle cerebral artery (MCA) aneurysms that were assessed using morphological variables to determine the parameters associated with aneurysm rupture.

Methods. Preoperative CT angiography (CTA) studies were evaluated using Slicer software to generate 3D models of the aneurysms and their surrounding vascular architecture. Morphological parameters examined in each model included 5 variables already defined in the literature (aneurysm size, aspect ratio, aneurysm angle, vessel angle, and size ratio) and 3 novel variables (flow angle, distance to the genu, and parent-daughter angle). Univariate and multivariate statistical analyses were performed to determine statistical significance.

Results. Between 2005 and 2008, 132 MCA aneurysms were treated at a single institution, and CTA studies of 79 aneurysms (40 ruptured and 39 unruptured) were analyzed. Fifty-three aneurysms were excluded because of reoperation (4), associated AVM (2), or lack of preoperative CTA studies (47). Ruptured aneurysms were associated with larger size, greater aspect ratio, larger aneurysm and flow angles, and smaller parent-daughter angle. Multivariate logistic regression revealed that aspect ratio, flow angle, and parent-daughter angle were the strongest factors associated with ruptured aneurysms.

Conclusions. Aspect ratio, flow angle, and parent-daughter angle are more strongly associated with ruptured MCA aneurysms than size. The association of parameters independent of aneurysm morphology with ruptured aneurysms suggests that these parameters may be associated with an increased risk of aneurysm rupture. These factors are readily applied in clinical practice and should be considered in addition to aneurysm size when assessing the risk of aneurysm rupture specific to the MCA location.

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Ruptured Intracranial Aneurysms With Small Basal Outpouching

Neurosurgery 71:994–1002, 2012

Recognizing an aneurysmal basal rupture using angiographic evaluation is crucial for optimal treatment.

OBJECTIVE: To evaluate the incidence of a small basal outpouching (the most common angiographic configuration suggesting a basal rupture), the incidence of a ruptured basal outpouching, and the results of surgical and endovascular treatments.

METHODS: The occurrence of small basal outpouchings was determined in the initial angiographic examinations of 471 patients with a ruptured aneurysm. Information was also obtained from patient charts, surgical and interventional reports, operative video records, and reviews of radiological investigations.

RESULTS: A small basal outpouching was identified in 41 (8.7%) of the 471 ruptured aneurysms. In the surgical series (n = 286), a basal rupture was identified in 8 (30.8%) of the 26 cases of a basal outpouching and successfully treated by aneurysm clip placement. In the endovascular series (n = 185), intraprocedural aneurysm rebleeding developed in 5 of the 15 patients (33.3%) with a basal outpouching, which was most commonly observed with anterior communicating artery aneurysms.

CONCLUSION: The current surgical series included a 9% incidence of ruptured intracranial aneurysms with a small basal outpouching, and a 31% incidence of these basal outpouchings being identified as the rupture point. The results also suggested that endovascular coiling of a basal outpouching carries a high risk of intraprocedural aneurysm rebleeding, whereas surgical clipping is safer and provides more protection against rebleeding of aneurysms with a basal rupture.

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Comparison of Superior-Level Facet Joint Violations During Open and Percutaneous Pedicle Screw Placement

Neurosurgery 71:962–970, 2012 

Superior-level facet joint violation by pedicle screws may result in increased stress to the level above the instrumentation and may contribute to adjacent segment disease. Previous studies have evaluated facet joint violations in open or percutaneous screw cases, but there are no reports describing a direct institutional comparison.

OBJECTIVE: To compare the incidence of superior-level facet violation for open vs percutaneous pedicle screws and to evaluate patient and surgical factors that affect this outcome.

METHODS: We reviewed 279 consecutive patients who underwent an index instrumented lumbar fusion from 2007 to 2011 for degenerative spine disease with stenosis with or without spondylolisthesis. We used a computed tomography grading system that represents progressively increasing grades of facet joint violation. Patient and surgical factors were evaluated to determine their impact on facet violation.

RESULTS: Our cohort consisted of 126 open and 153 percutaneous cases. Percutaneous procedures had a higher overall violation grade (P = .02) and a greater incidence of high-grade violations (P = .006) compared with open procedures. Bivariate analysis showed significantly greater violations in percutaneous cases for age,65 years, obesity, pedicle screws at L4, and 1- and 2-level surgeries. Multivariate analysis showed the percutaneous approach and depth of the spine to be independent risk factors for highgrade violations.

CONCLUSION: This study demonstrates greater facet violations for percutaneously placed pedicle screws compared with open screws.

 

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Arcuate fasciculus in brain tumor surgery

J Neurosurg 117:839–843, 2012 

Disturbance of the arcuate fasciculus in the dominant hemisphere is thought to be associated with language- processing disorders, including conduction aphasia. Although the arcuate fasciculus can be visualized in vivo with diffusion tensor imaging (DTI) tractography, its involvement in functional processes associated with language has not been shown dynamically using DTI tractography. In the present study, to clarify the participation of the arcuate fasciculus in language functions, postoperative changes in the arcuate fasciculus detected by DTI tractography were evaluated chronologically in relation to postoperative changes in language function after brain tumor surgery.

Methods. Preoperative and postoperative arcuate fasciculus area and language function were examined in 7 right-handed patients with a brain tumor in the left hemisphere located in proximity to part of the arcuate fasciculus. The arcuate fasciculus was depicted, and its area was calculated using DTI tractography. Language functions were measured using the Western Aphasia Battery (WAB).

Results. After tumor resection, visualization of the arcuate fasciculus was increased in 5 of the 7 patients, and the total WAB score improved in 6 of the 7 patients. The relative ratio of postoperative visualized area of the arcuate fasciculus to preoperative visualized area of the arcuate fasciculus was increased in association with an improvement in postoperative language function (p = 0.0039).

Conclusions. The role of the left arcuate fasciculus in language functions can be evaluated chronologically in vivo by DTI tractography after brain tumor surgery. Because increased postoperative visualization of the fasciculus was significantly associated with postoperative improvement in language functions, the arcuate fasciculus may play an important role in language function, as previously thought. In addition, postoperative changes in the arcuate fasciculus detected by DTI tractography could represent a predicting factor for postoperative language-dependent functional outcomes in patients with brain tumor.

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Anterior subtemporal approach for posterolateral brainstem cavernomas

Acta Neurochir (2012) 154:2009–2016

The neuronavigation-assisted anterior subtemporal approach is proposed in this article as an alternative to surgery of posterolateral brainstem cavernomas. Brainstem cavernomas represent a neurosurgical challenge because of the high morbidity and mortality rate related to their surgical removal. Several nerve nuclei, ascending and descending fibers make this region at high risk of serious postoperative deficits.

Methods Between 1998 and 2010, 24 patients underwent surgical removal of brainstem cavernomas in our institution. Ten of these patients presented a cavernous malformation in the posterolateral region of the brainstem and underwent surgical removal by means of a neuronavigation-assisted anterior subtemporal approach.

Results Lesion removal was complete for all patients. There were no cases of surgery-related death. Neurological status improved or remained unchanged after surgery in all cases. All patients presented good outcomes at 12 to 154 months’ follow-up (mean 70 months; GOS05 in 8/10 patients, 4 in 2/10 patients; mRS00–1 in all patients). Only one patient presented transient confusion, aphasia and seizures related to temporal lobe swelling, which resolved completely within a few days. One patient developed cranial nerve III palsy and left hemiparesis with gradual recovery.

Conclusions This approach represents a valid alternative to the “more classical” approaches for the surgery of posterolateral cavernomas of the pontomesenchephalic junction reaching the tentorial incisura, reducing the risk of damaging the vein of Labbé, temporal lobe swelling, cerebellar swelling, ophtalmoparesis, fourth ventricle cranial nerve nuclei lesions. Skeletonization of sigmoidal sinus provides with good outcomes, low morbidity and mortality.

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Pediatric Epilepsy Surgery: Long-term 5-Year Seizure Remission and Medication Use

Neurosurgery 71:985–993, 2012

It is unclear whether long-term seizure outcomes in children are similar to those in adult epilepsy surgery patients.

OBJECTIVE: To determine 5-year outcomes and antiepilepsy drug (AED) use in pediatric epilepsy surgery patients from a single institution.

METHODS: The cohort consisted of children younger than 18 years of age whose 5-year outcome data would have been available by 2010. Comparisons were made between patients with and without 5-year data (n = 338), patients with 5-year data for seizure outcome (n = 257), and seizure-free patients on and off AEDs (n = 137).

RESULTS: Five-year data were available from 76% of patients. More seizure-free patients with focal resections for hippocampal sclerosis and tumors lacked 5-year data compared with other cases. Of those with 5-year data, 53% were continuously seizure free, 18% had late seizure recurrence, 3% became seizure free after initial failure, and 25% were never seizure free. Patients were more likely to be continuously seizure free if their surgery was performed during the period 2001 to 2005 (68%) compared with surgery performed from 1996 to 2000 (61%), 1991 to 1995 (36%), and 1986 to 1990 (46%). More patients had 1 or fewer seizures per month in the late seizure recurrence (47%) compared with the not seizure-free group (20%). Four late deaths occurred in the not seizure-free group compared with 1 in the seizure-free group. Of patients who were continuously seizure free, 55% were not taking AEDs, and more cortical dysplasia patients (74%) had stopped taking AEDs compared with hemimegalencephaly patients (18%).

CONCLUSION: In children, 5-year outcomes improved over 20 years of clinical experience. Our results are similar to those of adult epilepsy surgery patients despite mostly extratemporal and hemispheric operations for diverse developmental etiologies.

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Surgical treatment of parasagittal and falcine meningiomas of the posterior third

Acta Neurochir (2012) 154:1987–1995

To the authors’ knowledge, meningiomas of the posterior third of the falx and the parasagittal sinus have never been specifically described to date and correlated visual outcome remains unclear. With this retrospective study we describe the clinical characteristics of these tumours, their surgical management, and the improvement in visual disturbances after surgery.

Methods Twenty-six consecutive patients (22 females, 4 males; mean age, 54 years) operated on for parasagittal (n022) and falcine (n04) meningioma between 1990 and 2010 were analysed retrospectively. Preoperative planning included magnetic resonance imaging (MRI) and magnetic resonance venography (MRV) or angiography. Sinus invasion was classified as normal, stenotic or occluded from the imaging findings and according to the Sindou classification from the intraoperative notes.

Results Visual disturbances and headache (in 21 and 14 cases, respectively) were the most commonly referred symptoms; visual field deficit was present in 19 patients. Simpson grade I was obtained in four patients, grade II in 15, grade III in three, and grade IV in four. The main limiting factor for total removal was sinus involvement. No perioperative deaths or relevant postoperative complications occurred. The mean follow-up was 107 months. Visual field deficit improved or resolved in almost half of the patients during the follow-up period. Three (12%) patients relapsed, two were treated with Gamma Knife surgery (stable at current writing) and the third died of disease progression.

Conclusions Outcome after surgery compares favourably with other parasagittal meningioma localisations and overall morbidity is negligible. Visual function is crucial for clinical outcome. Since an improvement of the deficit might still be possible, every effort should be undertaken to preserve the visual cortex.

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Comparison of 3 Reconstructive Techniques in the Surgical Management of Multilevel Cervical Spondylotic Myelopathy

Spine 2012 ; 37 : E1450 – E1458

A retrospective comparative study was performed in patients with 3-level cervical spondylotic myelopathy (CSM).

Objective. To compare the clinical outcomes, radiological parameters, and complication incidence of 3 reconstructive techniques after the anterior decompression of multilevel CSM.

Summary of Background Data. There has been growing interest in combination of anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF) for the treatment of multilevel CSM in recent years. However, the clinical efficacy and radiological outcomes of the hybrid decompression and fusion (HDF) have rarely been investigated.

Methods. A total of 180 consecutive patients with 3-level CSM undergoing the anterior decompression and fusion procedures from January 2003 to July 2010 were retrospectively investigated. According to various reconstructive techniques, the patients were divided into 3 groups: HDF, ACDF, and ACCF groups. The clinical effects and improvements of cervical and segmental lordosis in each group were assessed. In addition, the fusion rate, postoperative complications, and radiographical adjacent-level changes regarding each group were also evaluated.

Results. No statistical differences in clinical effects, restoration of cervical lordosis, and incidences of postoperative complications were found between the HDF and ACDF groups ( P > 0.05). The ACCF group has achieved clinical effects similar to the ACDF or HDF group ( P > 0.05), but it had more bleeding, lower fusion rate, and higher incidences of postoperative complications compared with the ACDF or HDF group ( P < 0.05). The improvements of the cervical and segmental lordosis in the ACCF group were significantly less than the ACDF or HDF group ( P < 0.05). There was no significant difference in radiographical adjacent-level changes among the 3 groups ( P > 0.05).

Conclusion. The HDF can be considered an effective and safe alternative procedure compared with ACDF in the treatment of the multilevel CSM, and ACCF should be the last option.

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Correlation between language function and the left arcuate fasciculus detected by diffusion tensor imaging tractography after brain tumor surgery

J Neurosurg 117:839–843, 2012

Disturbance of the arcuate fasciculus in the dominant hemisphere is thought to be associated with language-processing disorders, including conduction aphasia. Although the arcuate fasciculus can be visualized in vivo with diffusion tensor imaging (DTI) tractography, its involvement in functional processes associated with language has not been shown dynamically using DTI tractography. In the present study, to clarify the participation of the arcuate fasciculus in language functions, postoperative changes in the arcuate fasciculus detected by DTI tractography were evaluated chronologically in relation to postoperative changes in language function after brain tumor surgery.

Methods. Preoperative and postoperative arcuate fasciculus area and language function were examined in 7 right-handed patients with a brain tumor in the left hemisphere located in proximity to part of the arcuate fasciculus. The arcuate fasciculus was depicted, and its area was calculated using DTI tractography. Language functions were measured using the Western Aphasia Battery (WAB).

Results. After tumor resection, visualization of the arcuate fasciculus was increased in 5 of the 7 patients, and the total WAB score improved in 6 of the 7 patients. The relative ratio of postoperative visualized area of the arcuate fasciculus to preoperative visualized area of the arcuate fasciculus was increased in association with an improvement in postoperative language function (p = 0.0039).

Conclusions. The role of the left arcuate fasciculus in language functions can be evaluated chronologically in vivo by DTI tractography after brain tumor surgery. Because increased postoperative visualization of the fasciculus was significantly associated with postoperative improvement in language functions, the arcuate fasciculus may play an important role in language function, as previously thought. In addition, postoperative changes in the arcuate fasciculus detected by DTI tractography could represent a predicting factor for postoperative language-dependent functional outcomes in patients with brain tumor.

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Gross Total Resection Rates in Contemporary Glioblastoma Surgery: Results of an Institutional Protocol Combining 5-Aminolevulinic Acid Intraoperative Fluorescence Imaging and Brain Mapping

Neurosurgery 71:927–936, 2012

Complete resection of contrast-enhancing tumor has been recognized as an important prognostic factor in patients with glioblastoma and is a primary goal of surgery. Various intraoperative technologies have recently been introduced to improve glioma surgery.

OBJECTIVE: To evaluate the impact of using 5-aminolevulinic acid and intraoperative mapping and monitoring on the rate of complete resection of enhancing tumor (CRET), gross total resection (GTR), and new neurological deficits as part of an institutional protocol.

METHODS: One hundred three consecutive patients underwent resection of glioblastoma from August 2008 to November 2010. Eligibility for CRET was based on the initial magnetic resonance imaging assessed by 2 reviewers. The primary end point was the number of patients with CRET and GTR. Secondary end points were volume of residual contrast-enhancing tissue and new postoperative neurological deficits. RESULTS: Fifty-three patients were eligible for GTR/CRET (n = 43 newly diagnosed glioblastoma, n = 10 recurrent); 13 additional patients received surgery for GTR/CRET-ineligible glioblastoma. GTR was achieved in 96% of patients (n = 51, no residual enhancement . 0.175 cm3); CRET was achieved in 89% (n = 47, no residual enhancement). Postoperatively, 2 patients experienced worsening of preoperative hemianopia, 1 patient had a new mild hemiparesis, and another patient sustained sensory deficits.

CONCLUSION: Using 5-aminolevulinic acid imaging and intraoperative mapping/ monitoring together leads to a high rate of CRET and an increased rate of GTR compared with the literature without increasing the rate of permanent morbidity. The combination of safety and resection-enhancing intraoperative technologies was likely to be the major drivers for this high rate of CRET/GTR.

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