Maximizing Extent Of Resection Research Articles

Ultrasound-assisted resection of insular gliomas

BackgroundInsular gliomas’ management challenges are attributed to their complex shape, proximity to critical vasculature, and organization. However, cytoreductive surgery's role in maximal extent of resection (EOR) improves survival. Intraoperative ultrasound (IOUS) aids in defining tumor border, detecting residual, and guiding access.AimThe aim of this study was to assess the impact of using intraoperative ultrasound on the extent of resection of insular gliomas, and the postoperative outcomes in a prospective cohort of 20 patients operated at Alexandria main university hospital and followed up for a period of at least 3 months.ResultsThe Near total resection rate was 45% with 70% of patients having no neurological morbidity postoperatively. The median EOR was 81% with a range of 44 to 96%. The mean duration of IOUS setup was 19.6 ± 5.04 min, while the additional resection rate following IOUS assessment for residual tumor was 65% (n = 13). In addition, there was a significant increase in Karnofsky Performance Status (KPS) from the preoperative through to the 90-day follow-up period (p = 0.012). Finally, following multivariate linear regression analysis, the EOR was identified as having a statistically significant correlation with the postoperative KPS (p = 0.004).ConclusionIntraoperative ultrasonography is a valuable modality for strategizing the most efficient route to the tumor, promptly detecting any remaining tumor tissue, and optimizing the extent of resection for insular gliomas, while taking into consideration the phenomenon of brain shift.

Preoperative individual-target transcranial magnetic stimulation demonstrates an effect comparable to intraoperative direct electrical stimulation in language-eloquent glioma mapping and improves postsurgical outcome: A retrospective fiber-tracking and electromagnetic simulation study.

Efforts to resection of glioma lesions located in brain-eloquent areas must balance the extent of resection (EOR) and functional preservation. Currently, intraoperative direct electrical stimulation (DES) is the gold standard for achieving the maximum EOR while preserving as much functionality as possible. However, intraoperative DES inevitably involves risks of infection and epilepsy. The aim of this study was to verify the reliability of individual-target transcranial magnetic stimulation (IT-TMS) in preoperative mapping relative to DES and evaluate its effectiveness based on postsurgical outcomes. Sixteen language-eloquent glioma patients were enrolled. Nine of them underwent preoperative nTMS mapping (n=9, nTMS group), and the other seven were assigned to the non-nTMS group and did not undergo preoperative nTMS mapping (n=7). Before surgery, online IT-TMS was performed during a language task in the nTMS group. Sites in the cortex at which this task was disturbed in three consecutive trials were recorded and regarded as positive and designated nTMS hotspots (HSnTMS). Both groups then underwent awake surgery and intraoperative DES mapping. DES hotspots (HSDES) were also determined in a manner analogous to HSnTMS. The spatial distribution of HSnTMS and HSDES in the nTMS group was recorded, registered in a single brain template, and compared. The center of gravity (CoG) of HSnTMS (HSnTMS-CoG)-based and HSDES-CoG-based diffusion tensor imaging-fiber tracking (DTI-FT) was performed. The electromagnetic simulation was conducted, and the values were then compared between the nTMS and DES groups, as were the Western Aphasia Battery (WAB) scale and fiber-tracking values. HSnTMS and HSDES showed similar distributions (mean distance 6.32 ± 2.6mm, distance range 2.2-9.3mm, 95% CI 3.9-8.7mm). A higher fractional anisotropy (FA) value in nTMS mapping (P=0.0373) and an analogous fiber tract length (P=0.2290) were observed. A similar distribution of the electric field within the brain tissues induced by nTMS and DES was noted. Compared with the non-nTMS group, the integration of nTMS led to a significant improvement in language performance (WAB scores averaging 78.4 in the nTMS group compared with 59.5 in the non-nTMS group, P=0.0321 < 0.05) as well as in brain-structure preservation (FA value, P=0.0156; tract length, P=0.0166). Preoperative IT-TMS provides data equally crucial to DES and thus facilitates precise brain mapping and the preservation of linguistic function.

Predictive Evolution Factors of Incidentally Discovered Suspected Low-Grade Gliomas: Results From a Consecutive Series of 101 Patients.

Incidentally discovered suspected diffuse low-grade gliomas (LGGs) on brain imaging pose a challenge to neurosurgeons. Modern surgical series of LGGs favor early prophylactic surgery with a maximal extent of resection. However, some nonevolutive lesions may mimic LGGs on magnetic resonance imaging (MRI). To determine objective criteria to advocate surgical resection of an incidentally discovered suspected LGG based upon MRI findings. The prospective cohort of patients referred to our institution for an incidental finding suggestive of LGG was retrospectively reviewed. Stable lesions underwent systematic serial MRI follow-up, while evolutive lesions underwent prophylactic surgery under awake conditions. Initial clinico-radiological features were compared between stable and evolutive lesions in order to determine predictive criteria of further evolution. Among 101 patients referred for surgical resection of incidentally discovered suspected LGG in our center, 19 patients (18.8%) had nonevolutive MRI lesions after a mean follow-up of 46.9±34.9 mo. Insular topography (P=.003), higher mean volume at discovery (19.2vs 5.2 cm3, P<.001), and adjacent sulcal effacement (P=.001) were associated with evolutive lesions. Histopathological diagnosis of LGG was confirmed in all surgical cases. Increasing volume is an effective predictor of LGG diagnosis in incidental MRI findings, as all patients who subsequently underwent surgery had confirmed histopathological diagnosis of diffuse glioma. Approximately 18.8% of incidental findings were stable over time. Insular topography, adjacent sulcal effacement, and volume greater than 4.5 cm3 were predictive of further radiological progression. These significant elements will help neurosurgeons to define personalized strategies in this complex setting of incidental discovery.

Trans-Sylvian Resection of Giant Left Insular Glioma: Operative Technique and Nuances.

Insular glioma was considered a nonsurgical entity due to resection-associated morbidities. The advancement in neurosurgical techniques and adjuncts used in the last two decades made the resection of insular gliomas simpler for neurosurgeons with the maximum extent of resection and acceptable morbidity rates. The complex anatomy of this region remains a challenge for neurosurgeons and requires expertise. The key factors to achieve complete resection in the insular region are the thorough knowledge of surgical anatomy and meticulous microsurgical techniques. Intraoperative adjuncts such as image guidance along with cortical and subcortical mapping assist in excellent outcomes. In this study, we describe the operative technique and application of trans-Sylvian approach to do the compartmental dissection done by the senior author, along with challenges faced, with the hope to highlight the efficacy of the approach to achieve maximal resection of this entity without compromising patient's safety. A 32-year-old right-handed gentleman presented with episodes of excessive salivation, tingling sensation on the right side of the body along with nausea that lasted for 15-20 s for the last 8 months and one episode of speech arrest without any loss of consciousness and motor or sensory deficit. CEMRI of the brain was suggestive of left insular glioma. The patient underwent left pterional craniotomy, and gross total resection of the tumor was done using compartmental dissection. At follow-up after 1 month, the patient is seizure-free without any speech difficulty and motor or sensory deficit. Compartmental dissection of insular glioma is a safe and efficacious technique to achieve gross total resection of the tumor in this complex region without morbidity.

Postoperative outcomes following glioblastoma resection using a robot-assisted digital surgical exoscope: a case series.

Maximal extent of resection (EOR) of glioblastoma (GBM) is associated with greater progression free survival (PFS) and improved patient outcomes. Recently, a novel surgical system has been developed that includes a 2D, robotically-controlled exoscope and brain tractography display. The purpose of this study was to assess outcomes in a series of patients with GBM undergoing resections using this surgical exoscope. A retrospective review was conducted for robotic exoscope assisted GBM resections between 2017 and 2019. EOR was computed from volumetric analyses of pre- and post-operative MRIs. Demographics, pathology/MGMT status, imaging, treatment, and outcomes data were collected. The relationship between these perioperative variables and discharge disposition as well as progression-free survival (PFS) was explored. A total of 26 patients with GBM (median age = 57 years) met inclusion criteria, comprising a total of 28 cases. Of these, 22 (79%) tumors were in eloquent regions, most commonly in the frontal lobe (14 cases, 50%). The median pre- and post-operative volumes were 24.0 cc and 1.3 cc, respectively. The median extent of resection for the cohort was 94.8%, with 86% achieving 6-month PFS. The most common neurological complication was a motor deficit followed by sensory loss, while 8 patients (29%) were symptom-free. The robotic exoscope is safe and effective for patients undergoing GBM surgery, with a majority achieving large-volume resections. These patients experienced complication profiles similar to those undergoing treatment with the traditional microscope. Further studies are needed to assess direct comparisons between exoscope and microscope-assisted GBM resection.

The Impact of Surgery in IDH 1 Wild Type Glioblastoma in Relation With the MGMT Deregulation.

Object: The treatment of choice in glioblastoma (GBM) is the maximal surgical extent of resection (EOR) followed by adjuvant chemo-radiotherapy. Furthermore, methylguanine-DNA methyltransferase (MGMT) promoter methylation is associated with prolonged overall survival (OS) and progression free survival (PFS). The objective of the present study is correlate the biomolecular aspects in relation with EOR.Materials and methods: We analyzed a series of 116 patients with IDH-1 wild type GBM and different EOR (Gross Total Resection—GTR-, Partial Resection—PR- and Biopsy), treated with adjuvant chemo-radiotherapy. The MGMT status was analyzed in terms of promoter methylation and protein expression.Results: When GTR was possible, OS and PFS were significantly better compared to the other two groups (p = 0.001 and p = 0.035, respectively). MGMT methylation was significantly associated with better OS in the biopsy group (p = 0.022) and better OS and PFS in PR (p = 0.02 and p = 0.012, respectively), but not in the GTR group (p = 0.252 for OS, p = 0.256 for PFS) nor the PFS in the biopsy group (p = 0.259). MGMT protein expression levels do not show any association with OS and PFS, regardless of the type of surgery.Conclusions: Our study confirms the positive association of a safe maximal EOR with better OS and PFS, and indicates a positive prognostic value of MGMT methylation status only in case of the presence of residual tumor tissue. MGMT protein expression seems not to play a clinical role in relation with the type of surgery.

A new application of ultrasound-magnetic resonance multimodal fusion virtual navigation in glioma surgery.

Long-term survival and high-quality life of patients with gliomas depends on the extent of resection (EOR) and the protection of functional white matter fibers. The navigation system provides precise positioning for surgery based on preoperative magnetic resonance imaging (MRI) but the precision decreases when intraoperative brain drift occurs. Ultrasound (US) can support real-time imaging and correct brain shift. The real-time US-MRI multimodal fusion virtual navigation system (UMNS) is a new technique for glioma surgery. In order to obtain a maximum EOR and functional protection, this study aimed to explore the feasibility, efficiency, and safety of real-time UMNS for glioma surgery, and to evaluate the benefit of the new application by UMNS presetting markers between the tumor and functional white matter fiber surgery. A retrospective analysis included 45 patients who underwent glioma surgery, 19 patients with only intraoperative US, and 26 patients with UMNS. A preoperative plan was made by 3D-slicer software based on preoperative MRI. This was combined with a reconstruction of diffusion tensor imaging (DTI) that designed the important locations as "warning points" between functional white matter fibers and tumor. Following patient registration, markers were injected into preset "warning points" under image-guided UMNS in order to give us a warning during surgery in case of postoperative function deficits. The operating time, volumetric assessment in glioma resection, and postoperative complications were evaluated and used to compared those surgeries using intraoperative US (iUS) with those surgeries using intraoperate MRI (iMRI) navigation. A total of 45 patients underwent glioma surgery. Gross total removal (GTR) of iUS alone was achieved in 6 of 19 cases, while this was achieved in 22 of 26 cases with UMNS alone, demonstrating an improvement in rate of GTR from 31.58% to 84.62%, respectively. This may be attributable to the superior US image quality provided by UMNS. In 13 of 26 cases, there was improved image quality (from poor/moderate to moderate/good) with the aid of UMNS. In addition, the consistency of EOR of postoperative MRI evaluated by UMNS (92.31%) was higher than when using iUS alone (42.11%). The whole process of intraoperative scanning time and marker injection did not lead to a significant delay of the operating time compared to using iUS alone, and has been reported to be shorter than with iMRI as well. Furthermore, the percentage of postoperative morbidity in the UMNS group was lower than that in the iUS group (motor deficit: 11.54% vs. 42.11%; aphasia: P =3.85% vs. 31.58%, respectively). Real-time UMNS is an effective, timesaving technology that offers high quality intraoperative imaging. Injection markers between functional white matter fibers and tumor by UMNS can help to obtain a maximum EOR of glioma and functional protection postoperatively. The integration of iUS into the neuronavigation system offered quick and helpful intra-operative images.

Indications of 5-Aminolevulinic Acid and Intraoperative MRI in Glioma Surgery: First Cases in Latin America in a Single Reference Center

Introduction The improvement on the extent of resection (EOR) of gliomas with the combination of 5-aminolevulinic acid (5-ALA) and intraoperative magnetic resonance imaging (iMRI) has been demonstrated in previous studies. We present our results with the combined use of 5-ALA and (iMRI) in the surgery of glial lesions. Methods A total of 64 cases of patients with intracranial gliomas who underwent image-guided surgery using 5-ALA with and without (iMRI) were reviewed. All patients underwent an early postoperative MRI to evaluate the EOR. Other intra-operative techniques (awake surgery, electrophysiological stimulation and monitoring) were also performed according to the location of the tumor. Results A total of 18 tumors did not show intraoperative 5-ALA fluorescence (according to the World Health Organization [WHO] classification of tumors, 2 WHO-grade I, 14 WHO-grade II, 1 WHO-grade III and 1 WHO-grade IV), and 46 tumors showed intraoperative 5-ALA fluorescence (3 WHO-grade II, 3 WHO-grade III, 40 WHO-grade IV). In 28 of the 46 5-ALA positive cases, a safe 5-ALA free resection was achieved. In the 5-ALA negative cases, the (iMRI) findings guided the EOR, and complete resection was achieved in 11 cases. Complete resection was opted out in gliomas infiltrating eloquent areas. Conclusions The combined use of 5-ALA and IMRI showed improved results in glioma surgery, offering the safest maximal EOR. In the 5-ALA positive cases (mostly high-grade), fluorescence was a more useful tool. In the 5- ALA negative cases (mostly low-grade), the (iMRI) was decisive to guide the EOR of the tumor.

OUTCOMES OF 5-ALA FLIORESCECE-GUIDED SURGERY FOR HIGH GRADE G

High grade gliomas (HGG) are the most aggressive primary brain tumors. The extent of resection (EOR) is proved to be an important prognostic factor in patients with HGG. There are no yet published studies on the use of fluorescent-guided resection using 5-aminolevulinic acid (5-ALA) in HGG surgery, based on the comparison of neuroimaging characteristics, intraoperative parameters and clinical outcomes. The purpose of this study was to analyze the results of 5-ALA fluorescent-guided resection in patients with HGG by comparing neuroimaging characteristics, intraoperative parameters and clinical outcomes. Material and methods. The study included 48 patients (30 men and 18 women) aged 35 to 76 years (mean age 47.3 ± 8.4 years) with newly diagnosed HGG. The patients underwent fluorescent-guided surgery that permitted the intraoperative visualization of malignant glioma tissue and supported the neurosurgeon with real-time guidance for differentiating tumor from normal brain. The Karnofsky performance status (KPS) was assessed. Results. The maximum EOR (90–98 %) was achieved in 40 (83.3 %) patients with newly diagnosed HGG. The maximum EOR was performed in 28 (58.3 %) patients with glioblastomas and in 12 (25 %) patients with grade III gliomas (p=0.408) In addition, the maximum EOR was achieved by microneurosurgical removal of 9 (18.75 %) HGGs having a volume of ≥9 cm3 and 21 (43.75 %) of HGGs with a volume&lt;9 cm3 (p=0.029). The tumor boundaries detected by neuronavigation differed by fluorescence data in 28 (58.3 %) patients The divergence between neuronavigation and 5-ALA fluorescence was reported in 19 (39.5 %) patients with glioblastomas and in 3 (6.25 %) patients with grade III gliomas (p=0.014); and in 9 (39.5 %) and in 14 (29.1 %) patients affected with larger (≥9 cm3 ) and smaller (&lt;9 cm3 ) tumor, respectively (p=0.677). Overall, 36 (75 %) patients experienced an improvement in their KPS score, 9 (18.75 %) remained stable, and 3 (6.25 %) declined. Conclusion. The use of 5-ALA fluorescence in surgery for HGG makes it possible to achieve the gross total resection in most cases. The localization of HGGs and their size are the most important factors in achieving maximum EOR. Key words: high grade gliomas, fluorescent navigation, 5-aminolevulinic acid, extent of tumor resection&gt;&lt;9cm3 ) tumor, respectively (p=0.677). Overall, 36 (75 %) patients experienced an improvement in their KPS score, 9 (18.75 %) remained stable, and 3 (6.25 %) declined. Conclusion. The use of 5-ALA fluorescence in surgery for HGG makes it possible to achieve the gross total resection in most cases. The localization of HGGs and their size are the most important factors in achieving maximum EOR.

Volumetric Analysis Using Low-Field Intraoperative Magnetic Resonance Imaging for 168 Newly Diagnosed Supratentorial Glioblastomas: Effects of Extent of Resection and Residual Tumor Volume on Survival and Recurrence

Extent of resection (EOR) remains controversial in therapy for glioblastoma (GBM). However, an increasing number of studies favor maximum EOR as being associated with longer patient survival. Residual tumor volume (RTV) has also recently emerged as a prognostic factor. Low-field intraoperative magnetic resonance imaging (iMRI) has contributed to improve the EOR of GBM. The purpose of this study was to analyze the relationships between EOR/RTV and overall survival (OS)/progression-free survival (PFS) in patients with newly diagnosed GBM using low-field iMRI. Adult patients who underwent surgery for newly diagnosed supratentorial GBM between 2000 and 2012 were retrospectively reviewed. Three-dimensional volumetric tumor measurements were made. Multivariate analysis was used to evaluate the relationships between EOR/RTV and OS/PFS. Of 168 patients, 126 (75%) died and 154 (91%) showed tumor recurrence. Median OS and PFS for patients with iMRI were 19.3 months (95% confidence interval, 15.4-23.7 months) and 9.5 months (95% confidence interval, 7.8-10.8 months). Median preoperative tumor volume was 37.0 cm3 (interquartile range [IQR], 19.9-59.8 cm3). Median RTV was 0 cm3 (IQR, 0-1.6 cm3). Median EOR was 100% (IQR, 96.2%-100%). In multivariate analysis, after controlling for age and Karnofsky Performance Status, EOR andRTV remained significantly associated with survival (hazard ratio, 1.56; P= 0.018) and recurrence (hazard ratio, 1.53; P= 0.013). Maximum RTV for survival was 3 cm3. This volumetric analysis for low-field iMRI showed that both EOR and RTV were significantly associated with survival and recurrence. We determined a threshold RTV of 3 cm3 as the maximum RTV associated with survival.

NIMG-71ROBUSTNESS AND VALIDITY OF M1 DETERMINATION BY NAVIGATED TRANSCRANIAL MAGNETIC STIMULATION (NTMS) AND FUNCTIONAL MRI AS COMPARED TO INTRAOPERATIVE DIRECT CORTICAL STIMULATION (DCS)

INTRODUCTION: Imaging of the primary motor representation (M1) prior to brain tumour surgery is helpful to achieve a maximum extent of resection whilst preserving motor functions. To date, functional magnetic resonance imaging (fMRI) has been the most commonly used localizer technique for primary motor functioning. However, navigated transcranial magnetic stimulation (nTMS) gains increasing acceptance due to its high resolution and little dependence on the patients' compliance. We compared the congruency of nTMS vs. fMRI results with the gold standard method of direct cortical simulation (DCS). METHODS: 32 patients with intracerebral tumours underwent nTMS and fMRI prior to surgery. The cortical hot spots (HS) and Centres of Gravity (CoG) of M1 of the hand, the foot and the tongue representation were determined for each localizer technique and controlled by DCS. Euclidean distances (ED) between nTMS / fMRI and the respective DCS HS / CoG's were computed in 3D. Feasibility of both fMRI and nTMS were assessed in relation to the DCS results. RESULTS: Regarding the hand and the tongue representation, the CoG's of the nTMS maps were located significantly closer to the respective DCS-CoG's as compared to fMRI (hand [nTMS-DCS/ fMRI-DCS]: 9.7 ± 6.0 / 17.3 ± 9.6; p = 0.001; tongue: 9.4 ± 4.9 / 16.9 ± 5.9; p < 0.001 ). For the foot representation, a similar statistical trend was observed (12.2 ± 6.5 / 19.2 ± 12.9; p = 0.1). However, comparison of hot-spots did not reveal statistically significant differences. The feasibility of non-invasive localizer methods (fMRI: 100% / nTMS: 99%) was superior to DCS (71%). CONCLUSIONS: NTMS is a highly robust method for M1 mapping and seems to be superior to fMRI for mapping areas adjacent to brain tumours. Probably due to the limited depth of nTMS stimulation effects, nTMS is less clearly favourable for localizing the foot representation.

P157. Incidence and predictability of motor functioning after resection of pre-centrally located brain tumours

Objective In addition to a maximum extent of resection the preservation of important functions such as motor control are the major objectives in brain tumour surgery, not least with respect to consecutive treatments such as radio- or chemotherapy which require a good clinical state of the patients. Brain mapping techniques such as functional MRI and navigated transcranial magnetic stimulation (nTMS) have facilitated a lot the preoperative planning of the resection of eloquent brain tumours. However, the clinical course after resection of precentrally located brain tumours is often associated with hardly predictable, at least transient deterioration of motor functions. Methods A case series of 10 patients (7M/3F, mean age 57.8 yrs) with precentrally located brain tumours was collected within a prospective clinical trial between 2012 and 2014. All of them underwent preoperative nTMS mapping of the tumour-adjacent M1 areas (Nexstim eXimia 4.2). Tumour volume, oedema volume, the minimal distance between tumour/ oedema and the adjacent primary motor (M1) representation (hot spot, margin of map; iPlanNet) and the resting motor threshold (RMT) were compared to the neurological outcome which was evaluated before surgery, immediately after surgery (ICU), at discharge and 3–6 months later (follow-up). Results 7/10 of the patients deteriorated immediately after surgery (ICU). At discharge, 5 patients showed an improved motor status compared to admission (example: Fig. 1 ) and 3 patients had deteriorated of which at least one patient continued with slightly deteriorated motor functioning 3 months after surgery. In 4 of these patients, the neurological symptoms were totally reversible ( Table 1 ). The preliminary analysis revealed a weak correlation ( p Conclusion Aiming at the total resection of brain tumours located anteriorly to the M1 representation, a transient motor deficit should be expected in a high percentage (70% in this study). However, the deficit usually recovers well during the first week after surgery. Mapping techniques for the supplementary and pre-motor area may improve the predictability of transient motor deficits which is not only important for diagnostic decisions but also for the patient management with respect to presurgical consultancy. A novel protocol for non-invasive SMA-mapping by repetitive nTMS is currently under pre-clinical investigation by our group and showed promising preliminary results.

A better surgical resectability of WHO grade II gliomas is independent of favorable molecular markers.

A higher extent of resection (EOR) in WHO grade II gliomas (GIIG) is correlated with longer survival. However, the molecular markers also feature prognostic relevance. Here, we examined whether maximal EOR was related to the genetic profile. We retrospectively investigated the predictive value of 1p19q, IDH1, 53 expression and Ki67 index for the EOR in 200 consecutive GIIGs (2007-2013). Data were modeled in a linear model. The analysis was performed with two statistical methods (arcsin-sqrt and Beta-regression model with logit link). There was no deletion 1p19q in 118 cases, codeletion 1p19q (57 cases), single deletion 1p (4 cases) or19q (16 cases). 155 patients had a mutation of IDH1. p53 was graded in 4 degrees (0:92 cases, 1:52 cases, 2:31 cases, 3:8 cases). Mean Ki67 index was 5.2 % (range 1-20 %). Mean preoperative tumor volume was 60.8 cm(3) (range 3.3-250 cm(3)) and mean EOR was 0.917 (range 0.574-1). The statistical analysis was significant for a lower EOR in patients with codeletion 1p19q (OR 0.738, p = 0.0463) and with a single deletion 19q (OR 0.641, p = 0.0168). There was no significant correlation between IDH1 or p53 and the EOR. Higher Ki67 was marginally associated with higher EOR (p = 0.0603). The study demonstrates in a large cohort of GIIG that a higher EOR is not attributable to favorable genetic markers. This original result supports maximal surgical resection as an important therapeutic factor per se to optimize prognosis, independently of the molecular pattern.

Correlation of the extent of tumor volume resection and patient survival in surgery of glioblastoma multiforme with high-field intraoperative MRI guidance

Extent of resection (EOR) still remains controversial in therapy of glioblastoma multiforme (GBM). However, an increasing number of studies favor maximum EOR as being associated with longer patient survival. One hundred thirty-five GBM patients underwent tumor resection aided by 1.5T intraoperative MRI (iMRI) and integrated multimodal navigation. Tumor volume was quantified by manual segmentation. The influences of EOR, patient age, recurrent tumor, tumor localization, and gender on survival time were examined. Intraoperative MRI detected residual tumor volume in 88 patients. In 19 patients surgery was continued; further resection resulted in final gross total resection (GTR) for 9 patients (GTR increased from 47 [34.80%] to 56 [41.49%] patients). Tumor volumes were significantly reduced from 34.25 ± 23.68% (first iMRI) to 1.22 ± 16.24% (final iMRI). According to Kaplan-Meier estimates, median survival was 14 months (95% confidence interval [CI]: 11.7-16.2) for EOR ≥ 98% and 9 months (95% CI: 7.4-10.5) for EOR <98% (P< .0001); it was 9 months (95% CI: 7.3-10.7) for patients ≥ 65 years and 12 months (95% CI: 8.4-15.6) for patients <65 years (P < .05). Multivariate analysis showed a hazard ratio of 0.39 (95% CI: 0.24-0.63; P = .001) for EOR ≥ 98% and 0.61 (95% CI: 0.38-0.97; P < .05) for patient age <65 years. To our knowledge, this is the largest study including correlation of iMRI, tumor volumetry, and survival time. We demonstrate that navigation guidance and iMRI significantly contribute to optimal EOR with low postoperative morbidity, where EOR ≥ 98% and patient age <65 years are associated with significant survival advantages. Thus, maximum EOR should be the surgical goal in GBM surgery while preserving neurological function.

Quantification of Glioma Removal by Intraoperative High-Field Magnetic Resonance Imaging: An Update

The beneficial role of the extent of resection (EOR) in glioma surgery in correlation to increased survival remains controversial. However, common literature favors maximum EOR with preservation of neurological function, which is shown to be associated with a significantly improved outcome. In order to obtain a maximum EOR, it was examined whether high-field intraoperative magnetic resonance imaging (iMRI) combined with multimodal navigation contributes to a significantly improved EOR in glioma surgery. Two hundred ninety-three glioma patients underwent craniotomy and tumor resection with the aid of intraoperative 1.5 T MRI and integrated multimodal navigation. In cases of remnant tumor, an update of navigation was performed with intraoperative images. Tumor volume was quantified pre- and intraoperatively by segmentation of T2 abnormality in low-grade and contrast enhancement in high-grade gliomas. In 25.9% of all cases examined, additional tumor mass was removed as a result of iMRI. This led to complete tumor resection in 20 cases, increasing the rate of gross-total removal from 31.7% to 38.6%. In 56 patients, additional but incomplete resection was performed because of the close location to eloquent brain areas. Volumetric analysis showed a significantly (P < .01) reduced mean percentage of tumor volume following additional further resection after iMRI from 33.5% ± 25.1% to 14.7% ± 23.3% (World Health Organization [WHO] grade I, 32.8% ± 21.9% to 6.1% ± 18.8%; WHO grade II, 24.4% ± 25.1% to 10.8% ± 11.0%; WHO grade III, 35.1% ± 27.3% to 24.8% ± 26.3%; WHO grade IV, 34.2% ± 23.7% to 1.2% ± 16.2%). MRI in conjunction with multimodal navigation and an intraoperative updating procedure enlarges tumor-volume reduction in glioma surgery significantly without higher postoperative morbidity.

Independent association of extent of resection with survival in patients with malignant brain astrocytoma

With recent advances in the adjuvant treatment of malignant brain astrocytomas, it is increasingly debated whether extent of resection affects survival. In this study, the authors investigate this issue after primary and revision resection of these lesions. The authors retrospectively reviewed the cases of 1215 patients who underwent surgery for malignant brain astrocytomas (World Health Organization [WHO] Grade III or IV) at a single institution from 1996 to 2006. Patients with deep-seated or unresectable lesions were excluded. Based on MR imaging results obtained < 48 hours after surgery, gross-total resection (GTR) was defined as no residual enhancement, near-total resection (NTR) as having thin rim enhancement of the resection cavity only, and subtotal resection (STR) as having residual nodular enhancement. The independent association of extent of resection and subsequent survival was assessed via a multivariate proportional hazards regression analysis. Magnetic resonance imaging studies were available for review in 949 cases. The mean age and mean Karnofsky Performance Scale (KPS) score at time of surgery were 51 +/- 16 years and 80 +/- 10, respectively. Surgery consisted of primary resection in 549 patients (58%) and revision resection for tumor recurrence in 400 patients (42%). The lesion was WHO Grade IV in 700 patients (74%) and Grade III in 249 (26%); there were 167 astrocytomas and 82 mixed oligoastrocytoma. Among patients who underwent resection, GTR, NTR, and STR were achieved in 330 (35%), 388 (41%), and 231 cases (24%), respectively. Adjusting for factors associated with survival (for example, age, KPS score, Gliadel and/or temozolomide use, and subsequent resection), GTR versus NTR (p < 0.05) and NTR versus STR (p < 0.05) were independently associated with improved survival after both primary and revision resection of glioblastoma multiforme (GBM). For primary GBM resection, the median survival after GTR, NTR, and STR was 13, 11, and 8 months, respectively. After revision resection, the median survival after GTR, NTR, and STR was 11, 9, and 5 months, respectively. Adjusting for factors associated with survival for WHO Grade III astrocytoma (age, KPS score, and revision resection), GTR versus STR (p < 0.05) was associated with improved survival. Gross-total resection versus NTR was not associated with an independent survival benefit in patients with WHO Grade III astrocytomas. The median survival after primary resection of WHO Grade III (mixed oligoastrocytomas excluded) for GTR, NTR, and STR was 58, 46, and 34 months, respectively. In the authors' experience with both primary and secondary resection of malignant brain astrocytomas, increasing extent of resection was associated with improved survival independent of age, degree of disability, WHO grade, or subsequent treatment modalities used. The maximum extent of resection should be safely attempted while minimizing the risk of surgically induced neurological injury.

Long-term brain plasticity allowing a multistage surgical approach to World Health Organization Grade II gliomas in eloquent areas

Although the goal of surgery for World Health Organization Grade II gliomas is maximal extent of resection, complete tumor removal is not always possible when the glioma involves eloquent areas. The authors propose a multistage surgical approach to highly crucial areas that are classically considered inoperable, enabling optimization of the extent of resection while avoiding permanent cognitive deficits due to induced functional reshaping in the interim between the 2 consecutive operations. To demonstrate such plasticity, the authors used a combination of sequential functional MR imaging and intraoperative electrical stimulation mapping before and during surgeries spaced by several years in 2 patients who each underwent 2 separate resections of Grade II gliomas located in the left dominant premotor area. During several years of follow-up after the first procedure, both patients had unremarkable examination results and normal socioprofessional lives. There was no malignant transformation. Based on their experience with these cases, the authors suggest that in cases of incomplete glioma removal, a second operation before anaplasia should be considered, made possible by brain reorganization after the first operation.