Quantitative Anatomical Comparison of Surgical Approaches to Meckel's Cave.

BACKGROUND: Meckel's cave is a challenging surgical target due to its deep location and proximity to vital neurovascular structures. Surgeons have developed various microsurgical transcranial approaches (MTAs) to access it, but there is no consensus on the best method. Newer endoscopic approaches have also emerged. This study seeks to quantitatively compare these surgical approaches to Meckel's cave, offering insights into surgical volumes and exposure areas. METHODS: Fifteen surgical approaches were performed bilaterally in six specimens, including the pterional approach (PTA), fronto-temporal-orbito-zygomatic approach (FTOZA), subtemporal approach (STA), Kawase approach (KWA), retrosigmoid approach (RSA), retrosigmoid approach with suprameatal extension (RSAS), endoscopic endonasal transpterygoid approach (EETPA), inferolateral transorbital approach (ILTEA) and superior eyelid approach (SEYA). All the MTAs were performed both with 10 mm and 15 mm of brain retraction, to consider different percentages of surface exposure. A dedicated navigation system was used to quantify the surgical working volumes and exposure of different areas of Meckel's cave (ApproachViewer, part of GTx-Eyes II, University Health Network, Toronto, Canada). Microsurgical transcranial approaches were quantified with two different degrees of brain retraction (10 mm and 15 mm). Statistical analysis was performed using a mixed linear model with bootstrap resampling. RESULTS: The RSAS with 15 mm of retraction offered the maximum exposure of the trigeminal stem (TS). If compared to the KWA, the RSA exposed more of the TS (69% vs. 46%; p = 0.01). The EETPA and ILTEA exposed the Gasserian ganglion (GG) mainly in the anteromedial portion, but with a significant 20% gain in exposure provided by the EETPA compared to ILTEA (42% vs. 22%; p = 0.06). The STA with 15 mm of retraction offered the maximum exposure of the GG, with a significant gain in exposure compared to the STA with 10 mm of retraction (50% vs. 35%; p = 0.03). The medial part of the three trigeminal branches was mainly exposed by the EETPA, particularly for the ophthalmic (66%) and maxillary (83%) nerves. The EETPA offered the maximum exposure of the medial part of the mandibular nerve, with a significant gain in exposure compared to the ILTEA (42% vs. 11%; p = 0.01) and the SEY (42% vs. 2%; p = 0.01). The FTOZA offered the maximum exposure of the lateral part of the ophthalmic nerve, with a significant gain of 67% (p = 0.03) and 48% (p = 0.04) in exposure compared to the PTA and STA, respectively. The STA with 15 mm of retraction offered the maximum exposure of the lateral part of the maxillary nerve, with a significant gain in exposure compared to the STA with 10 mm of retraction (58% vs. 45%; p = 0.04). The STA with 15 mm of retraction provided a significant exposure gain of 23% for the lateral part of the mandibular nerve compared to FTOZA with 15 mm of retraction (p = 0.03). CONCLUSIONS: The endoscopic approaches, through the endonasal and transorbital routes, can provide adequate exposure of Meckel's cave, especially for its more medial portions, bypassing the impediment of major neurovascular structures and significant brain retraction. As far as the most lateral portion of Meckel's cave, MTA approaches still seem to be the gold standard in obtaining optimal exposure and adequate surgical volumes.

Resilience in Lower Grade Glioma Patients.

Current data show that resilience is an important factor in cancer patients' well-being. We aim to explore the resilience of patients with lower grade glioma (LGG) and the potentially influencing factors. We performed a cross-sectional assessment of adult patients with LGG who were enrolled in the LoG-Glio registry. By phone interview, we administered the following measures: Resilience Scale (RS-13), distress thermometer, Montreal Cognitive Assessment Test for visually impaired patients (MoCA-Blind), internalized stigmatization by brain tumor (ISBI), Eastern Cooperative Oncological Group performance status (ECOG), patients' perspective questionnaire (PPQ) and typical clinical parameters. We calculated correlations and multivariate regression models. Of 74 patients who were assessed, 38% of those showed a low level of resilience. Our results revealed significant correlations of resilience with distress (p < 0.001, −0.49), MOCA (p = 0.003, 0.342), ECOG (p < 0.001, −0.602), stigmatization (p < 0.001, −0.558), pain (p < 0.001, −0.524), and occupation (p = 0.007, 0.329). In multivariate analyses, resilience was negatively associated with elevated ECOG (p = 0.020, ß = −0.383) and stigmatization levels (p = 0.008, ß = −0.350). Occupation showed a tendency towards a significant association with resilience (p = 0.088, ß = −0.254). Overall, low resilience affected more than one third of our cohort. Low functional status is a specific risk factor for low resilience. The relevant influence of stigmatization on resilience is a novel finding for patients suffering from a glioma and should be routinely identified and targeted in clinical routine.

A Continuous Correlation Between Residual Tumor Volume and Survival Recommends Maximal Safe Resection in Glioblastoma Patients: A Nomogram for Clinical Decision Making and Reference for Non-Randomized Trials.

OBJECTIVE: The exact role of the extent of resection or residual tumor volume on overall survival in glioblastoma patients is still controversial. Our aim was to create a statistical model showing the association between resection extent/residual tumor volume and overall survival and to provide a nomogram that can assess the survival benefit of individual patients and serve as a reference for non-randomized studies. METHODS: In this retrospective multicenter cohort study, we used the non-parametric Cox regression and the parametric log-logistic accelerated failure time model in patients with glioblastoma. On 303 patients (training set), we developed a model to evaluate the effect of the extent of resection/residual tumor volume on overall survival and created a score to estimate individual overall survival. The stability of the model was validated by 20-fold cross-validation and predictive accuracy by an external cohort of 253 patients (validation set). RESULTS: We found a continuous relationship between extent of resection or residual tumor volume and overall survival. Our final accelerated failure time model (pseudo R2 = 0.423; C-index = 0.749) included residual tumor volume, age, O6-methylguanine-DNA-methyltransferase methylation, therapy modality, resectability, and ventricular wall infiltration as independent predictors of overall survival. Based on these factors, we developed a nomogram for assessing the survival of individual patients that showed a median absolute predictive error of 2.78 (mean: 1.83) months, an improvement of about 40% compared with the most promising established models. CONCLUSIONS: A continuous relationship between residual tumor volume and overall survival supports the concept of maximum safe resection. Due to the low absolute predictive error and the consideration of uneven distributions of covariates, this model is suitable for clinical decision making and helps to evaluate the results of non-randomized studies.

Neuro-oncological patients' and caregivers' psychosocial burden during the COVID-19 pandemic-A prospective study with qualitative content analysis.

OBJECTIVE: The COVID-19 pandemic may reinforce psychosocial distress of neuro-oncological patients. We aimed to (1) differentiate the burden caused by the pandemic versus the tumor and (2) establish topics relevant for brain tumor patients (BTPs) and caregivers. METHODS: Patients and caregivers were prospectively assessed from April 2020-July 2020 by a 10-item comprising interview over the phone, including qualitative and quantitative questions. They were quantitatively evaluated i.a. by the distress thermometer (DT, score 1-10). The qualitative questions were analyzed using structured content analysis: The interview questions defined the main categories. Subcategories were derived by an inductive approach assessing the frequency of patients' and caregivers' answers. RESULTS: A total of 69 patients and 20 caregivers were interviewed; n = 36 were female (49%), mean age was 53 years (range 32-81). Patients' disease-related DT scores were higher than the COVID-19-related DT scores: the median of the disease-related DT score was 7 (range 2-10) versus median of COVID-19-related distress: 5.0 (range 2-7). Caregivers perceived a higher burden due to the disease (DT median disease: 8; range 2-10 vs. DT pandemic: 3, range 0-10). A total of five main and 21 subcategories were elaborated, most frequently mentioned were "restrictions in public and private affairs" (28%), "changes in the psychological well-being" (23%), "limited social interaction by contact restriction" (25%). Subcategories relevant for caregivers were similar to those of BTPs. CONCLUSION: A considerable proportion of patients and caregivers still perceived the brain tumor disease as more burdensome than the pandemic. We established main and subcategories of interview items possibly of great relevance to patients during these difficult times, which could be implemented in the content-related adaption of the psychosocial assessment.

Microvascular decompression for treating classical trigeminal neuralgia: can we offer the gold standard therapy to older patients?

PURPOSE: Microvascular decompression is the most successful procedure for treating classic trigeminal neuralgia. However, due to the risks of surgery and anesthesia, the procedure is performed less frequently in older patients. The aim of the study is to investigate the intraoperative and perioperative morbidity in older patients who underwent this surgical treatment. METHODS: Patients who underwent microvascular decompression in our department between 2004 and 2016 were divided into two age groups (A: < 69 years old, n = 114; B: ≥ 70 years old, n = 47). Retrospectively, the pre-, intra- and postoperative data were analyzed. RESULTS: Older patients showed a statistically significant prolonged duration of symptoms until surgery (mean 127 months vs. 70 months; p < 0.001). They also showed a significantly increased necessity for duroplasty (p = 0.015), but with no increased incidence of postoperative cerebrospinal fluid leakage or rhinoliquorrhea. A comparable postoperative course was found in both groups. Over 90% in both groups had a significantly postoperative improvement. There were no cardiopulmonary complications or infections in either group. In the 3-month follow-up, there was a comparable success of pain reduction and no increased incidence of sensory disturbances. CONCLUSIONS: Based on the high chances of success and low morbidity, microvascular decompression should also be offered to older patients with anesthesiologic agreement.

Survey of the management of perioperative bridging of anticoagulation and antiplatelet therapy in neurosurgery.

BACKGROUND: A growing number of patients on anticoagulation or antiplatelet therapy (APT) are planned for elective surgery. The management of perioperative anticoagulation and APT is challenging because it must balance the risk of thromboembolism and bleeding, and specific recommendations for the management of bridging in neurosurgical patients are lacking. We surveyed German neurosurgical centers about their management of perioperative bridging of anticoagulation and APT to provide an overview of the current bridging policy. METHOD: From April to August 2016, all German neurosurgical departments were invited to participate in the survey. We used SurveyMonkey to compose ten questions and to conduct the survey, and we defined three different approaches for the perioperative management of patients on a preexisting medication: medication will be discontinued (A) with perioperative "bridging" and (B) without perioperative bridging, or (C) medication will be continued perioperatively. RESULTS: Out of 141 respondents, 84 (60%) partially and 77 (55%) fully completed the questionnaire. No defined policy for the perioperative management of anticoagulation and APT was established in 60.7% (51/84) of participating centers. The perioperative management of anticoagulation and APT varied widely among different centers in all items of the questionnaire; for example, in the group of patients at high risk for thromboembolism, acetylsalicylic acid was discontinued in 22%, bridged in 35%, and continued in 35% of centers. CONCLUSIONS: There is significant uncertainty regarding the management of perioperative bridging of anticoagulation and APT in neurosurgery because of a lack of prospective and limited retrospective data.

Cerebrovascular Insult as Presenting Symptom of Neurofibromatosis Type 2 in Children, Adolescents, and Young Adults.

Background and Purpose: Neurofibromatosis Type 2 (NF2) is an autosomal-dominant tumor-prone disorder characterized by the manifestations of central nervous system lesions. However, the first clinical signs of disease are often non-tumorous. Cerebrovascular insults are known in NF2, however, not yet described as first symptom in young NF2 patients. Methods: Magnetic resonance image scans of 298 NF2 patients treated in our neurofibromatosis center in Tübingen from 2003 to 2017 were retrospectively evaluated focusing on presence of aneurysms and ischemic stroke. Clinical data were used to clarify whether or not ischemic stroke or aneurysm rupture were the first presentation of disease. Blood of the patients were subjected to genetic screening for constitutional NF2 mutations. Results: We identified 5 cases under age of 25 years with aneurysms or ischemic stroke. Among them three had ischemic strokes of the brain stem and one aneurysmal subarachnoid hemorrhage as the first symptom of the disease. Incidental finding of 2 intracranial aneurysm occurred in one patient. All aneurysms were clipped. Patients with ischemia suffered from dysarthria, gait disturbances, dizziness, and hemiparesis. Residual signs of hemiparesis and dysarthria persisted in one patient. All others fully recovered from the cerebrovascular insult. Bilateral vestibular schwannomas and intracranial meningiomas were found in all five patients. Conclusions: A cerebrovascular insult in the vertebrobasilar territory may occur as first symptom of disease in young NF2 patients. The brain stem seems to be especially prone to ischemic stroke. Multicenter studies on large NF2 cohorts are needed to determine the prevalence and pattern of cerebrovascular insults and disease in NF2 patients.

Intraspinal intradural nodular fasciitis mimicking glioblastoma metastasis: a case report.

We report the case of a 78-year-old male patient suffering from right temporal glioblastoma with radiographic meningeal tumor spread. During the further course of the disease he developed a rapidly progressive paraplegia. An magnetic resonance imaging scan showed a contrast enhancing an intraspinal intradural lesion with compression of the myelon on segment Th 8/9. With a high suspicion of a spinal metastasis of the known glioblastoma, emergency spinal decompression and resection of the intradural mass was performed. However, histopathological evaluation revealed nodular fasciitis without any signs of glial origin.

Concomitant Occurrence of Vestibular Schwannoma and Epidermoid Cyst in Neurofibromatosis: Case description and Review of the Literature

We report a case of a 16-year-old female patient harboring neurofibromatosis type 2 who presented with bilateral hearing impairment, which was on the left side, as well as facial paresis (House-Brackmann grade III) and ataxic gait. A magnetic resonance imaging (MRI) exam evidenced bilateral lesions in the cerebellopontine angles (CPAs) with extension into the internal acoustic meatus, and an additional lesion in the right CPA with radiological characteristics of an epidermoid cyst. The patient was submitted to microsurgical resection, confirming a collision of a vestibular schwannoma and an epidermoid cyst in the right CPA. In the present case report, we describe the first case reported in the literature with preoperative diagnostic work-up, intraoperative findings, postoperative course of the patient, as well as a detailed literature review of these specific coinciding pathologies, denoting the importance of further genomic studies regarding multiple central nervous system (CNS) lesions.

Relatamos o caso de uma paciente de 16 anos de idade com neurofibromatose tipo II com deficiência auditiva bilateral, pior no ouvido esquerdo, assim como paresia facial (HouseBrackmann grau III) e ataxia. Estudo de ressonância magnética comprovou lesão bilateral nos ângulos cerebelopontinos (ACPs) com extensão ao meato acústico interno, e uma lesão adicional no ACP direito com características radiológicas de um cisto epidermoide. A paciente foi submetida a ressecção microcirúrgica, confirmando a colisão de um schwannoma vestibular com um cisto epidermoide no ACP direito. No presente estudo, descrevemos o primeiro caso relatado na literatura com trabalho diagnóstico pré-operatório, resultados intraoperatórios, evolução da paciente no pós-operatório, assim como revisão detalhada da literatura específica sobre essas patologias, demonstrando a importância de mais estudos genômicos sobre as múltiplas lesões do sistema nervoso central (SNC).

Prolonged Temozolomide Maintenance Therapy in Newly Diagnosed Glioblastoma.

BACKGROUND: The impact of prolonging temozolomide (TMZ) maintenance beyond six cycles in newly diagnosed glioblastoma (GBM) remains a topic of discussion. We investigated the effects of prolonged TMZ maintenance on progression-free survival (PFS) and overall survival (OS). PATIENTS AND METHODS: In this retrospective single-center cohort study, we included patients with GBM who were treated with radiation therapy with concomitant and adjuvant TMZ. For analysis, patients were considered who either completed six TMZ maintenance cycles (group B), continued with TMZ therapy beyond six cycles (group C), or stopped TMZ maintenance therapy within the first six cycles (group A). Patients with progression during the first six TMZ maintenance cycles were excluded. RESULTS: Clinical data from 107 patients were included for Kaplan-Meier analyses and 102 for Cox regressions. Median PFS times were 8.1 months (95% confidence interval [CI] 6.1-12.4) in group A, 13.7 months (95% CI 10.6-17.5) in group B, and 20.9 months (95% CI 15.2-43.5) in group C. At first progression, response rates of TMZ/lomustine rechallenge were 47% in group B and 13% in group C. Median OS times were 12.7 months (95% CI 10.3-16.8) in group A, 25.2 months (95% CI 17.7-55.5) in group B, and 28.6 months (95% CI 24.4-open) in group C. Nevertheless, multivariate Cox regression for patients in group C compared with group B that accounted for imbalances of other risk factors showed no different relative risk (RR) for OS (RR 0.77, p = .46). CONCLUSION: Our data do not support a general extension of TMZ maintenance therapy beyond six cycles. The Oncologist 2017;22:570-575 IMPLICATIONS FOR PRACTICE: Radiation therapy with concomitant and adjuvant temozolomide (TMZ) maintenance therapy is still the standard of care in patients below the age of 65 years in newly diagnosed glioblastoma. However, in clinical practice, many centers continue TMZ maintenance therapy beyond six cycles. The impact of this continuation is controversial and has not yet been addressed in prospective randomized clinical trials. We compared the effect of more than six cycles of TMZ in comparison with exactly six cycles on overall survival (OS) and progression-free survival (PFS) by multivariate analysis and found a benefit in PFS but not OS. Thus, our data do not suggest prolonging TMZ maintenance therapy beyond six cycles, which should be considered in neurooncological practice.

Risk Factors of Preoperative and Early Postoperative Seizures in Patients with Meningioma: A Retrospective Single-Center Cohort Study.

OBJECTIVE: Well-defined risk factors for the identification of patients with meningioma who might benefit from preoperative or early postoperative seizure prophylaxis are unknown. We investigated and quantified risk factors to determine individual risks of seizure occurrence in patients with meningioma. METHODS: A total of 634 adult patients with meningioma were included in this retrospective cohort study. Patient gender and age, tumor location, grade and volume, usage of antiepileptic drugs (AEDs) and extent of resection were determined. RESULTS: Preoperative and early postoperative seizures occurred in 15% (n = 97) and 5% (n = 21) of the patients, respectively. Overall, 502 and 418 patients were eligible for multivariate logistic regression analyses of preoperative and early postoperative seizures, respectively. Male gender (odds ratio [OR], 2.06; P = 0.009), a non-skull base location (OR, 4.43; P < 0.001), and a tumor volume of >8 cm3 (OR, 3.05; P = 0.002) were associated with a higher risk of preoperative seizures and were used to stratify the patients into 3 prognostic groups. The high-risk subgroup of patients with meningioma showed a seizure rate of >40% (OR, 9.8; P < 0.001). Only a non-skull base tumor location (OR, 2.61; P = 0.046) was identified as a significant risk factor for early postoperative seizures. AEDs did not reduce early postoperative seizure occurrence. CONCLUSIONS: Seizure prophylaxis might be considered for patients at high risk of developing seizures who are for other reasons being considered for watchful waiting instead of resection. In contrast, our data do not provide any evidence of the efficacy of perioperative AEDs in patients with meningioma.

Petrosectomy and Topographical Anatomy in Traditional Kawase and Posterior Intradural Petrous Apicectomy (PIPA) Approach: An Anatomical Study.

OBJECTIVE: To compare the anatomical exposure and petrosectomy extent in the Kawase and posterior intradural petrous apicectomy (PIPA) approaches. METHODS: Kawase and PIPA approaches were performed on 4 fixed cadaveric heads (3 alcohol-fixed, 1 formaldehyde-fixed silicone-injected; 4 Kawase and 4 PIPA approaches). The microsurgical anatomy was examined by means of Zeiss Opmi CS/NC-4 microscopes. HD Karl Storz Endoscopes (AIDA system) were used to display intradural exposure. Petrosectomy volumes was assessed by comparing pre- and postoperative thin-slice computed tomography scans (Analyze 12.0; AnalyzeDirect Mayo Clinic). RESULTS: The Kawase approach exposed the rhomboid fossa with Meckel's cave extradurally, the upper half of the clivus, superior cerebellopontine angle, ventrolateral brainstem, the intrameatal region, basilar apex, and the preganglionic root of cranial nerve (CN) V, CN III-IV-VI intradurally. The PIPA approach exposed the cerebello-pontine angle with CN VI-XII, Meckel's cave, CN III-V, and the middle and lower clivus intradurally from a posterior view. The area of surgical exposure is wide in both approaches; however, the volume of petrosectomy, the working angle, and surgical corridor differ significantly. CONCLUSIONS: The Kawase approach allows wide exposure of the middle cranial fossa (MCF) and posterior cranial fossa, requiring extradural temporal lobe retraction and an extradural petrosectomy with preservation of the internal acoustic meatus and cochlea. No temporal lobe retraction and direct control of neurovascular structures make the PIPA approach a valid alternative for lesions extending mostly in the Posterior cranial fossa with minor extension in the MCF. The longer surgical corridor, cerebellar retraction, and limited exposure of the anterior brainstem make this approach less indicated for lesions with major extension in the MCF and the anterior cavernous sinus.

Evidence of Resting-state Activity in Propofol-anesthetized Patients with Intracranial Tumors.

RATIONALE AND OBJECTIVES: Resting-state (RS) networks, revealed by functional magnetic resonance imaging (fMRI) studies in healthy volunteers, have never been evaluated in anesthetized patients with brain tumors. Our purpose was to examine the presence of residual brain activity on the auditory network during propofol-induced loss of consciousness in patients with brain tumors. MATERIALS AND METHODS: Twenty subjects with intracranial masses were prospectively studied by means of intraoperative RS-fMRI acquisitions before any craniectomy. After performing single-subject independent component analysis, spatial maps and time courses were assigned to an auditory RS network template from the literature and compared via spatial regression coefficients. RESULTS: All fMRI data were of sufficient quality for further postprocessing. In all but two patients, the RS functional activity of the auditory network could be successfully mapped. In almost all patients, contralateral activation of the auditory network was present. No significant difference was found between the mean distance of the RS activity clusters and the lesion periphery for tumors located in the temporal gyri vs. those in other brain regions. The spatial deviation between the activated cluster in our experiment and the template was significantly (P = 0.04) higher in patients with tumors located in the temporal gyri than in patients with tumors located in other regions. CONCLUSIONS: Propofol-induced anesthesia in patients with intracranial lesions does not alter the blood-oxygenation level-depended signal, and independent component analysis of intraoperative RS-fMRI may allow assessment of the auditory network in a clinical setting.

Predictors of preoperative and early postoperative seizures in patients with intra-axial primary and metastatic brain tumors: A retrospective observational single center study.

OBJECTIVE: Antiepileptic treatment of brain tumor patients mainly depends on the individual physician's choice rather than on well-defined predictive factors. We investigated the predictive value of defined clinical parameters to formulate a model of risk estimations for subpopulations of brain tumor patients. METHODS: We enclosed 650 patients > 18 years of age who underwent brain tumor surgery and included a number of clinical data. Logistic regressions were performed to determine the effect sizes of seizure-related risk factors and to develop prognostic scores for the occurrence of preoperative and early postoperative seizures. RESULTS: A total of 492 patients (334 gliomas) were eligible for logistic regression for preoperative seizures, and 338 patients for early postoperative seizures. Age ≤ 60 years (odds ratio [OR] = 1.66, p = 0.020), grades I and II glioma (OR = 4.00, p = 0.0002), total tumor/edema volume ≤ 64cm(3) (OR = 2.18, p = 0.0003), and frontal location (OR = 2.28, p = 0.034) demonstrated an increased risk for preoperative seizures. Isocitrate-dehydrogenase mutations (OR = 2.52, p = 0.026) were an independent risk factor in the glioma subgroup. Age ≥ 60 years (OR = 3.32, p = 0.041), total tumor/edema volume ≤ 64cm(3) (OR = 3.17, p = 0.034), complete resection (OR = 15.50, p = 0.0009), diencephalic location (OR = 12.2, p = 0.013), and high-grade tumors (OR = 5.67, p = 0.013) were significant risk factors for surgery-related seizures. Antiepileptics (OR = 1.20, p = 0.60) did not affect seizure occurrence. For seizure occurrence, patients could be stratified into 3 prognostic preoperative and into 2 prognostic early postoperative groups. INTERPRETATION: Based on the developed prognostic scores, seizure prophylaxis should be considered in high-risk patients and patient stratification for prospective studies may be feasible in the future.

Intraoperative assistive technologies and extent of resection in glioma surgery: a systematic review of prospective controlled studies.

Several studies published to date about glioma surgery have addressed the validity of using novel technologies for intraoperative guidance and potentially improved outcomes. However, most of these reports are limited by questionable methods and/or by their retrospective nature. In this work, we performed a systematic review of the literature to address the impact of intraoperative assistive technologies on the extent of resection (EOR) in glioma surgery, compared to conventional unaided surgery. We were also interested in two secondary outcome variables: functional status and progression-free survival. We primarily used PubMed to search for relevant articles. Studies were deemed eligible for our analysis if they (1) were prospective controlled studies; (2) used EOR as their primary target outcome, assessed by MRI volumetric analysis; and (3) had a homogeneous study population with clear inclusion criteria. Out of 493 publications identified in our initial search, only six matched all selection criteria for qualitative synthesis. Currently, the evidence points to 5-ALA, DTI functional neuronavigation, neurophysiological monitoring, and intraoperative MRI as the best tools for improving EOR in glioma surgery. Our sample and conclusions were limited by the fact that studies varied in terms of population characteristics and in their use of different volumetric analyses. We were also limited by the low number of prospective controlled trials available in the literature. Additional evidence-based high-quality studies assessing cost-effectiveness should be conducted to better determine the benefits of intraoperative assistive technologies in glioma surgery.

Spectroscopy imaging in intraoperative MR suite: tissue characterization and optimization of tumor resection.

BACKGROUND: MR spectroscopy (MRS) measurements are common practice in the preoperative diagnostic regimen, but no evidence exists concerning their value in intraoperative MRI (iMRI) setting. We sought to examine the feasibility of intraoperative MRS and to assess the clinical value of the method in optimizing the gliomas resection. METHODS: Forty-five patients with low- and high-grade gliomas underwent iMRI-assisted surgery, including pre- and intraoperative MRS measurements. During the intraoperative control scan, MRS was performed at the resection margin. Peak areas under the major metabolites (N-acetyl-aspartate: NAA; choline: Cho; and creatine: Cr) resonances were estimated, and their ratios entered in the statistical analysis. RESULTS: Concerning preoperative MRS imaging, mean Cho/NAA and Cho/Cr ratios in low-grade gliomas were 2.3 and 1.2, respectively. The average Cho/NAA and Cho/Cr ratios in the high-grade gliomas were 3.9 and 2.3, respectively. In 12 out of 20 cases with low-grade gliomas, intraoperative conventional MR imaging showed suspected tumor remnant and MRS diagnosed correctly the tissue signal alterations in 10 out of those 12 cases. MRS could characterize gadolinium-enhancing or non-enhancing tumor remnants in all cases with high-grade tumors. Thus, it could help achieve total tumor resection unless the latter was contraindicated due to increased risk of neurological complications. CONCLUSIONS: MR spectroscopy (MRS) in an iMRI setting is feasible, facilitating preoperative glioma staging as well as satisfactory characterization of suspected tumor remnants. Thus, it may be helpful tool for an extended tumor resection.

Combined spinal cord and peripheral nerve field stimulation for persistent post-herniorrhaphy pain.

OBJECTIVES: Chronic post-hernia pain is a common complication after inguinal herniorrhaphies. Peripheral nerve field stimulation (PNFS) and spinal cord stimulation (SCS) are two new promising treatment modalities. Four patients with persistent neuropathic post-hernia pain were recruited for this prospective study. MATERIALS AND METHODS: Electrodes were inserted into the epidural space of the spinal canal and into the subcutaneous tissue in the inguinal region during a single surgical procedure. During a 14-day trial, double-blind stimulation was performed via an external stimulator: three days using the spinal electrode (SCS), three days using the inguinal electrode (PNFS), three days using both (SCS + PNFS), and five days off, with an alternating order from patient to patient. During the trial, pain intensity was assessed thrice daily by the visual analog scale. Additionally, pain intensity and quality of life (QOL) were assessed before and after surgical intervention by the Brief Pain Inventory, SF36 scale, and Pain Disability Index. RESULTS: All patients had a marked pain reduction during the trial phase, and this reduction was more prominent when both electrodes were activated simultaneously (p < 0.001). At the late follow-up, a significant pain reduction and improvement of QOL was observed in three patients. CONCLUSIONS: Both SCS and PNFS are effective in treating post-hernia pain, but the magnitude of pain reduction was more prominent with concomitant stimulation. Combined PNFS and SCS should be considered for patients with a less than optimal response to either SCS or PNFS. More studies are necessary to address the cost-effect issues of this new approach to treatment.

Intraoperative visualization of residual tumor: the role of perfusion-weighted imaging in a high-field intraoperative magnetic resonance scanner.

BACKGROUND: High-field, intraoperative magnetic resonance imaging (iMRI) achieves free tumor margins in glioma surgery by involving anatomic neuronavigation and sophisticated functional imaging. OBJECTIVE: To evaluate the role of perfusion-weighted iMRI as an aid to detect residual tumor and to guide its resection. METHODS: Twenty-two patients undergoing intraoperative scanning (in a dual-room 1.5-T magnet setting) during the resection of high-grade gliomas were examined with perfusion-weighted iMRI. The generated relative cerebral blood volume (rCBV) maps were scrutinized for any hot spots indicative of tumor remnants, and region-of-interest analysis was performed. Differences among the rCBV region-of-interest estimates in residual tumor, free tumor margins, and normal white matter were analyzed. Histopathology of the tissue specimens and the neurosurgeon's intraoperative macroscopic estimations were considered the reference standards. RESULTS: In all cases, diagnostic rCBV perfusion maps were generated. Interpretation of perfusion maps demonstrated that gross total resection of gliomas was achieved in 4 of 22 cases (18%), which was macroscopically and histopathologically verified, whereas in 18 of 22 cases (82%), the perfusion-weighted iMRI revealed hot spots indicating subtotal tumor removal. The latter proved to be true in all but 1 case. The receiver-operating characteristic curves of the qualitative visual and quantitative analyses showed excellent sensitivity and specificity rates. Statistical analysis demonstrated statistically significant differences for the mean rCBV and maximum rCBV between residual disease and tumor-free margins (P = .002 for both). CONCLUSION: Perfusion-weighted iMRI may be implemented easily into imaging protocols and may assist the surgeon in detecting residual tumor volume.

Lumbar spinal stenosis in elderly patients: is a unilateral microsurgical approach sufficient for decompression?

OBJECT: For the treatment of lumbar spinal stenosis, less invasive procedures, which preserve maximal bony and ligamentous structures, have been recommended to reduce associated morbidity. The authors examined the outcome after decompression of spinal stenosis in the elderly by comparing 3 different surgical approaches. Their focus was whether a unilateral microsurgical decompression provided sufficient outcomes in the elderly population. METHODS: The authors investigated 108 elderly patients (age ≥ 60 years) with lumbar spinal stenosis (mean age 71 years [range 60-93 years]) who underwent surgery between 2004 and June 2006 at the authors' institution. Three different modes of decompression were analyzed in this study: a unilateral partial hemilaminectomy, a hemilaminectomy, and a laminectomy. The outcome was assessed 12 months postoperatively using the Quebec Back Pain Disability Scale and the Hannover Functional Back Pain Questionnaire. RESULTS: The authors performed a unilateral partial hemilaminectomy in 53 patients (49%). Patients who underwent unilateral partial hemilaminectomies achieved favorable results of at least 80% as assessed using the Quebec Back Pain Disability Scale and Hannover Functional Back Pain Questionnaire. Hemilaminectomies were performed in 45 patients (41.7%), and laminectomies were performed in 10 patients (9.3%). However, there was no statistically significant difference between the various techniques regarding the postoperative results (p < 0.05). CONCLUSIONS: Laminectomies did not show any advantage when compared with unilateral transmedian approaches. A unilateral partial hemilaminectomy combined with a transmedian decompression sufficiently treated the stenosis. This method seemed advantageous in minimizing the procedure and associated morbidity in this elderly population. Further investigations with long-term results (> 5 years) are still necessary.