Intraoperative imaging technology to maximise extent of resection for glioma: a network meta-analysis.

BACKGROUND: Multiple studies have identified the prognostic relevance of extent of resection in the management of glioma. Different intraoperative technologies have emerged in recent years with unknown comparative efficacy in optimising extent of resection. One previous Cochrane Review provided low- to very low-certainty evidence in single trial analyses and synthesis of results was not possible. The role of intraoperative technology in maximising extent of resection remains uncertain. Due to the multiple complementary technologies available, this research question is amenable to a network meta-analysis methodological approach. OBJECTIVES: To establish the comparative effectiveness and risk profile of specific intraoperative imaging technologies using a network meta-analysis and to identify cost analyses and economic evaluations as part of a brief economic commentary. SEARCH METHODS: We searched CENTRAL (2020, Issue 5), MEDLINE via Ovid to May week 2 2020, and Embase via Ovid to 2020 week 20. We performed backward searching of all identified studies. We handsearched two journals, Neuro-oncology and the Journal of Neuro-oncology from 1990 to 2019 including all conference abstracts. Finally, we contacted recognised experts in neuro-oncology to identify any additional eligible studies and acquire information on ongoing randomised controlled trials (RCTs). SELECTION CRITERIA: RCTs evaluating people of all ages with presumed new or recurrent glial tumours (of any location or histology) from clinical examination and imaging (computed tomography (CT) or magnetic resonance imaging (MRI), or both). Additional imaging modalities (e.g. positron emission tomography, magnetic resonance spectroscopy) were not mandatory. Interventions included fluorescence-guided surgery, intraoperative ultrasound, neuronavigation (with or without additional image processing, e.g. tractography), and intraoperative MRI. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed the search results for relevance, undertook critical appraisal according to known guidelines, and extracted data using a prespecified pro forma. MAIN RESULTS: We identified four RCTs, using different intraoperative imaging technologies: intraoperative magnetic resonance imaging (iMRI) (2 trials, with 58 and 14 participants); fluorescence-guided surgery with 5-aminolevulinic acid (5-ALA) (1 trial, 322 participants); and neuronavigation (1 trial, 45 participants). We identified one ongoing trial assessing iMRI with a planned sample size of 304 participants for which results are expected to be published around winter 2020. We identified no published trials for intraoperative ultrasound. Network meta-analyses or traditional meta-analyses were not appropriate due to absence of homogeneous trials across imaging technologies. Of the included trials, there was notable heterogeneity in tumour location and imaging technologies utilised in control arms. There were significant concerns regarding risk of bias in all the included studies. One trial of iMRI found increased extent of resection (risk ratio (RR) for incomplete resection was 0.13, 95% confidence interval (CI) 0.02 to 0.96; 49 participants; very low-certainty evidence) and one trial of 5-ALA (RR for incomplete resection was 0.55, 95% CI 0.42 to 0.71; 270 participants; low-certainty evidence). The other trial assessing iMRI was stopped early after an unplanned interim analysis including 14 participants; therefore, the trial provided very low-quality evidence. The trial of neuronavigation provided insufficient data to evaluate the effects on extent of resection. Reporting of adverse events was incomplete and suggestive of significant reporting bias (very low-certainty evidence). Overall, the proportion of reported events was low in most trials and, therefore, issues with power to detect differences in outcomes that may or may not have been present. Survival outcomes were not adequately reported, although one trial reported no evidence of improvement in overall survival with 5-ALA (hazard ratio (HR) 0.82, 95% CI 0.62 to 1.07; 270 participants; low-certainty evidence). Data for quality of life were only available for one study and there was significant attrition bias (very low-certainty evidence). AUTHORS' CONCLUSIONS: Intraoperative imaging technologies, specifically 5-ALA and iMRI, may be of benefit in maximising extent of resection in participants with high-grade glioma. However, this is based on low- to very low-certainty evidence. Therefore, the short- and long-term neurological effects are uncertain. Effects of image-guided surgery on overall survival, progression-free survival, and quality of life are unclear. Network and traditional meta-analyses were not possible due to the identified high risk of bias, heterogeneity, and small trials included in this review. A brief economic commentary found limited economic evidence for the equivocal use of iMRI compared with conventional surgery. In terms of costs, one non-systematic review of economic studies suggested that, compared with standard surgery, use of image-guided surgery has an uncertain effect on costs and that 5-ALA was more costly. Further research, including completion of ongoing trials of ultrasound-guided surgery, is needed.

ANTECEDENTES: En múltiples estudios se ha identificado la importancia pronóstica del alcance de la resección en el tratamiento del glioma. En los últimos años han surgido diferentes tecnologías intraoperatorias con una eficacia comparativa desconocida para optimizar el alcance de la resección. Una revisión Cochrane anterior proporcionó evidencia de certeza baja a muy baja en los análisis de un solo ensayo y no fue posible la síntesis de los resultados. La función de la tecnología intraoperatoria para maximizar el alcance de la resección aún no está clara. Debido a las múltiples tecnologías complementarias disponibles, esta pregunta de investigación se presta a un enfoque metodológico de metanálisis en red. OBJETIVOS: Establecer el perfil comparativo de efectividad y riesgo de determinadas tecnologías de imagenología intraoperatorias mediante un metanálisis en red e identificar análisis de costos y evaluaciones económicas como parte de un breve comentario económico. MÉTODOS DE BÚSQUEDA: Se hicieron búsquedas en CENTRAL (2020, número 5), MEDLINE vía Ovid hasta la semana 2 de mayo de 2020, y Embase vía Ovid hasta la semana 20 de 2020. Se realizó una búsqueda retrospectiva de todos los estudios identificados. Se hicieron búsquedas manuales en dos revistas, Neuro­oncology y Journal of Neuro­oncology, desde 1990 hasta 2019, y se incluyeron todos los resúmenes de congresos. Finalmente, se estableció contacto con expertos reconocidos en neurooncología para identificar cualquier estudio elegible adicional y obtener información sobre los ensayos controlados aleatorizados (ECA) en curso. CRITERIOS DE SELECCIÓN: ECA que evaluaron a personas de todas las edades con presuntos tumores gliales nuevos o recidivantes (de cualquier ubicación o histología) a partir del examen clínico y la imagenología (tomografía computarizada [TC] o imagenología de resonancia magnética [IRM], o ambas). Las modalidades adicionales de imagenología (p.ej., tomografía de emisión de positrones, espectroscopia de resonancia magnética) no fueron obligatorias. Las intervenciones incluyeron cirugía guiada por fluorescencia, ecografía intraoperatoria, neuronavegación (con o sin procesamiento adicional de las imágenes, p.ej., tractografía) e IRM intraoperatoria. OBTENCIÓN Y ANÁLISIS DE LOS DATOS: Dos autores de la revisión, de forma independiente, evaluaron los resultados de la búsqueda en cuanto a su relevancia, realizaron la evaluación crítica según las guías conocidas y extrajeron los datos mediante un formulario predeterminado. RESULTADOS PRINCIPALES: Se identificaron cuatro ECA, que utilizaron diferentes tecnologías de imagenología intraoperatorias: la resonancia magnética (IRM) intraoperatoria (dos ensayos, con 58 y 14 participantes); la cirugía guiada por fluorescencia con ácido 5­aminolevulínico (5­ALA) (un ensayo, 322 participantes); y la neuronavegación (un ensayo, 45 participantes). Se identificó un ensayo en curso que evaluó la IRM con un tamaño de la muestra planificado de 304 participantes, del que se espera la publicación de los resultados alrededor del invierno de 2020. No se han identificado ensayos publicados sobre la ecografía intraoperatoria. Los metanálisis en red o los metanálisis tradicionales no fueron apropiados debido a la falta de ensayos homogéneos en tecnologías de imagenología. De los ensayos incluidos, hubo una notable heterogeneidad en la localización de los tumores y en las tecnologías de imagenología utilizadas en los brazos control. Hubo inquietudes significativas con respecto al riesgo de sesgo en todos los estudios incluidos. Un ensayo de IRM encontró un aumento en la extensión de la resección (razón de riesgos [RR] para la resección incompleta 0,13; intervalo de confianza [IC] del 95%: 0,02 a 0,96; 49 participantes; evidencia de certeza muy baja) y un ensayo de 5­ALA (RR para la resección incompleta 0,55; IC del 95%: 0,42 a 0,71; 270 participantes; evidencia de certeza baja). El otro ensayo que evaluó la IRM se interrumpió de forma temprana después de un análisis intermedio no planificado que incluyó 14 participantes; por lo tanto, el ensayo proporciona evidencia de calidad muy baja. El ensayo de neuronavegación no proporcionó datos suficientes para evaluar los efectos sobre el grado de resección. El informe de los eventos adversos fue incompleto e indicó la presencia de sesgo de informe significativo (evidencia de certeza muy baja). En general, la proporción de eventos informados fue baja en la mayoría de los ensayos y, por lo tanto, pueden haber estado presentes o no problemas relacionados con el poder estadístico suficiente para detectar diferencias en los desenlaces. No se informó adecuadamente sobre los desenlaces de supervivencia, aunque un ensayo no informó evidencia de mejora en la supervivencia general con 5­ALA (cociente de riesgos instantáneos [CRI] 0,82; IC del 95%: 0,62 a 1,07; 270 participantes; evidencia de certeza baja). Solo hubo datos disponibles sobre la calidad de vida de un estudio, con un sesgo de desgaste significativo (evidencia de certeza muy baja). CONCLUSIONES DE LOS AUTORES: Las tecnologías de imagenología intraoperatoria, específicamente la IRM y el 5­ALA, pueden ser beneficiosas para maximizar el grado de resección en los participantes con glioma de grado alto. Sin embargo, lo anterior se basa en evidencia de certeza baja a muy baja. Por lo tanto, los efectos neurológicos a corto y a largo plazo no están claros. No están claros los efectos de la cirugía guiada por imágenes sobre la supervivencia general, la supervivencia sin progresión ni la calidad de vida. No fue posible realizar metanálisis en red ni tradicionales debido al alto riesgo de sesgo identificado, a la heterogeneidad y a los ensayos pequeños incluidos en esta revisión. Un comentario económico breve encontró evidencia económica limitada sobre el uso equívoco de la IRM en comparación con la cirugía convencional. En cuanto a los costos, una revisión no sistemática de estudios económicos indicó que, en comparación con la cirugía estándar, el uso de la cirugía guiada por imágenes no tiene un efecto claro sobre los costos y que el ácido 5­aminolevulínico fue más costoso. Se necesitan estudios de investigación adicionales, incluida la finalización de los ensayos en curso sobre la cirugía guiada por ecografía.

Access to Technology and Education for the Development of Minimally Invasive Spine Surgery Techniques in Latin America.

OBJECTIVE: To evaluate access to the technologies and education needed to perform minimally invasive spine surgery (MISS) in Latin America. METHODS: We designed a questionnaire to evaluate surgeons' practice characteristics, access to different technologies, and training opportunities for MISS techniques. The survey was sent to members and registered users of AO Spine Latin from January 6-20, 2020. The major variables studied were nationality, specialty (orthopedics or neurosurgery), level of hospital (primary, secondary, tertiary), number of surgeries performed per year by the spine surgeon, types of spinal pathologies commonly managed, and number of MISS performed per year. Other variables involved specific access to different technologies: intraoperative fluoroscopy, percutaneous screws, cages, tubular retractors, microscopy, intraoperative computed tomography, neuronavigation imaging, and bone morphogenetic protein. Finally, participants were asked about main obstacles to performing MISS and their access to education on MISS techniques in their region. RESULTS: The questionnaires were answered by 306 members of AO Spine Latin America across 20 different countries. Most answers were obtained from orthopedic surgeons (57.8%) and those with over 10 years of experience (42.4%). Most of the surgeons worked in private practice (46.4%) and performed >50 surgeries per year (44.1%), but only 13.7% performed >50 MISS per year, mainly to manage degenerative pathologies (87.5%). Most surgeons always had access to fluoroscopy (79%). Only 26% always had access to percutaneous screws, 24% to tubular retractors, 34.3% to cages (anterior lumbar interbody fusion, lateral lumbar interbody fusion, or transforaminal lumbar interbody fusion), and 43% to microscopy. Regarding technologies, 71% reported never having access to navigation, 83% computed tomography, and 69.3% bone morphogenetic protein. The main limitations expressed for widely used MISS technologies were the high implant costs (69.3%) and high navigation costs (49.3%). Most surgeons claimed access to online education activities (71%), but only 44.9% reported access to face-to-face events and 28.8% to hands-on activities, their limited access largely because the courses were expensive (62.7%) or few courses were available on MISS in their region (51.3%). CONCLUSIONS: Most surgeons in Latin America have limited resources to perform MISS, even in private practice. The main constraints are implant costs, access to technologies, and limited face-to-face educational opportunities.

Are There Differences in Accuracy or Outcomes Scores Among Navigated, Robotic, Patient-specific Instruments or Standard Cutting Guides in TKA? A Network Meta-analysis.

BACKGROUND: Several kinds of cutting guides, including patient-specific instrumentation, navigation, standard cutting guides, accelerometer-based navigation, and robotic guidance, are available to restore a planned alignment during TKA. No previous study has simultaneously compared all of these devices; a network meta-analysis is an especially appealing method because it allows comparisons across approaches that were not compared head-to-head in individual randomized controlled trials. QUESTIONS/PURPOSES: We performed a network meta-analysis to determine whether novel approaches to achieving implant alignment, such as patient-specific instrumentation, navigation, accelerometer-based navigation, and robotic guidance, provide any advantage over standard cutting guides in terms of: (1) hip-knee-ankle (HKA) alignment outliers greater than ± 3°, (2) outcome scores (1989 - Knee Society Score and WOMAC score) measured 6 months after surgery, or (3) femoral and tibial implant malalignment (greater than ± 3°), taken separately, in the frontal and sagittal plane, as well as other secondary outcomes including validated outcome scores 1 and 2 years after surgery. METHODS: In our network meta-analysis, we included randomized controlled trials comparing the different cutting guides by using at least one of the previously specified criteria, without limitation on language or date of publication. We searched electronic databases, major orthopaedic journals, proceedings of major orthopaedic meetings, ClinicalTrials.gov, and the World Health Organization's International Clinical Trials Registry Platform until October 1, 2018. This led to the inclusion of 90 randomized controlled trials involving 9389 patients (mean age 68.8 years) with 10,336 TKAs. Two reviewers independently selected trials and extracted data. The primary outcomes were the proportion patients with malalignment of the HKA angle (defined as HKA > 3° from neutral) and the Knee Society Score and WOMAC scores at 6 months postoperatively. We combined direct and indirect comparisons using a Bayesian network meta-analysis framework to assess and compare the effect of different cutting guides on outcomes. Bayesian estimates are based on the posterior distribution of an endpoint and are called credible intervals. Usually the 95% credible interval, corresponding to a posterior probability of 0.95 that the endpoint lies in the interval, is computed. Unlike the frequentist approach, the Bayesian approach does not allow the calculation of the p value. RESULTS: The proportion of HKA outliers was lower with navigation than with patient-specific instrumentation (risk ratio 0.46 [95% credible interval (CI) 0.34 to 0.63]) and standard cutting guides (risk ratio 0.45 [95% CI 0.37 to 0.53]); however, this corresponded to an actual difference of only 12% of patients for navigation versus 21% of patients for patient-specific instrumentation, and 12% of patients for navigation versus 25% for standard cutting guides. We found no differences for other comparisons between different cutting guides, including robotics and the accelerometer. We found no differences in the Knee Society Score or WOMAC score between the different cutting guides at 6 months. Regarding secondary outcomes, navigation reduced the risk of frontal and sagittal malalignments for femoral and tibial components compared with the standard cutting guides, but none of the other cutting guides showed superiority for the other secondary outcomes. CONCLUSIONS: Navigation resulted in approximately 10% fewer patients having HKA outliers of more than 3°, without any corresponding improvement in validated outcomes scores. It is unknown whether this incremental reduction in the proportion of patients who have alignment outside a window that itself has been called into question will justify the increased costs and surgical time associated with the approach. We believe that until or unless these new approaches either (1) convincingly demonstrate superior survivorship, or (2) convincingly demonstrate superior outcomes, surgeons and hospitals should not use these approaches since they add cost, have a learning curve (during which some patients may be harmed), and have the risks associated with uncertainty of novel surgical approaches. LEVEL OF EVIDENCE: Level I, therapeutic study.

Computer-assisted brain surgery (neuronavigation) in Abuja, North Central Nigeria: A 3-year retrospective review and practical challenges.

INTRODUCTION: Neuronavigation has become a standard of care in contemporary neurosurgery since more than two decades and is gradually being embraced in our local practice. It is, therefore, important to share our local experience, including practical challenges encountered with this technology. AIMS AND OBJECTIVES: The aim of this study is to review and present our early experience with stealth neuronavigation and to discuss the practical challenges encountered with the application of this technology in this environment. METHODOLOGY: Retrospective review of all consecutive cases over a 3-year period (January 2016-December 2018). Admitting diagnosis, operations, histological diagnosis, adjuvant treatments and 6 months outcome were the major study parameters. Procedural challenges were also highlighted. Data were analysed using simple descriptive statistics, and results were presented in tables and figures. RESULTS: A total of 30 procedures were conducted. Nineteen males and 11 females (male: female = 1.7:1). Youngest was 8 months, oldest was 71 years, mean = 39 and standard deviation (SD) = 19.3. Operations performed were resection of mass lesion 18/30 (60%) and biopsy of mass lesion in 12/30 (40%) cases. Histological diagnostic yield was 100%. Mean duration of hospital stay was 2 days (SD = 0.25) for the biopsy group and 8 days (SD = 1.7) for the resection group. At 6 months review, 10/30 (33.3%) have died following progression and/or complications of their primary pathology. CONCLUSIONS: Wide spectrum of brain lesions were approached confidently with precision and minimal morbidity. No procedure-related mortality was recorded. Adjuvant treatments were easily deployed in line with a precise histological diagnosis. Practical challenges did not compromise the navigation process.

[3D-Navigated Implantation of Pedicle Screws in the Cervical Spine - Experience and Analysis of Complications]. / 3-D-navigierte Pedikelschrauben der Halswirbelsäule ­ Erfahrungen und Komplikationsanalyse.

Background: Placing transpedicular screws in the cervical spine is a special challenge for spine surgeons, due to the anatomical features of this part of the spine. During the last 15 years, computer-aided navigation systems have been developed to facilitate this procedure and to make it safer for patients. One option is navigation by intraoperatively acquired data sets with the use of an 3D C-arm. Patients/Material and methods: Our retrospective study evaluates transpedicular screws in the cervical spine placed by 3D C-arm navigation, within a 6 year period in a level 1 trauma centre. We recorded epidemiological data, operation time and especially general adverse events, as well as revision surgery, including reasons for revision. We used a C-arm Arcardis Orbic 3D (Siemens, Munich), connected to a navigation system (VectorVision, Brainlab, Munich). Results: Between July 2007 and July 2013, 207 transpedicular screws were placed in 58 patients. The main indications were trauma (69 %), rheumatic diseases (20.7 %) and tumour (8.6 %). The most commonly instrumented cervical spine segments were C2 (53.5 %)%), C7 (10.3 %) and C5 (8.6 %). In nearly 95 % of the cases, we performed an intraoperative 3D scan after screw or k-wire placement to control the screw position. We found unacceptable malposition in 7.2 % of patients. This was corrected at once. Ten patients had to be revised: seven times due to wound problems, twice because of implant failure and once for treatment of CSF leakage. Three screws (1.5 %) led to injuries of the vertebral artery, once with a lethal outcome. Analysis of these cases showed that the 3D scan gave reduced data quality, due to reduced bone density or anatomical factors. Conclusion: Intraoperative 3D C-arm navigation seems to be a reliable option for transpedicular screw placement in the cervical spine. Complication rates were comparable to published values. 7.2 % of all screws were corrected intraoperatively after a control scan. Therefore possible revisions could be avoided during primary surgery. Analysis of problematic cases led to a change in our treatment strategy: in patients with poor bone quality and/or anatomical problems which lead to 3D scans of poor quality, we avoid transpedicular screw placement in C6 or higher, in order to prevent injuries of the vertebral artery.

Image Guidance for Placement of Ommaya Reservoirs: Comparison of Fluoroscopy and Frameless Stereotactic Navigation in 145 Patients.

OBJECTIVE: Ommaya reservoirs are used for administration of intrathecal chemotherapy and cerebrospinal fluid sampling. Ventricular catheter placement for these purposes requires a high degree of accuracy. Various options exist to optimize catheter placement. We analyze a cohort of patients receiving catheters using 2 different technologies. METHODS: Retrospective chart review was performed on patients undergoing Ommaya reservoir placement between 2011 and 2014. Most procedures were assisted by either frameless stereotactic neuronavigation or fluoroscopic guidance with pneumoencephalogram. Catheter accuracy, revision rates, perioperative complications, and operative time were measured. Preoperative similarities and differences in diagnosis, demographics, and ventricular size were also recorded to avoid a biased assessment of our results. RESULTS: One-hundred and forty-five patients were included, 57 using fluoroscopic guidance and 88 using frameless stereotaxy. Common diagnoses in both groups were lymphoma and leptomeningeal disease. Qualitative measures of catheter placement accuracy showed no significant difference between the 2 groups. Proximity to the foramen of Monro favored fluoroscopy by a small margin (8.6 mm vs. 10.2 mm, P = 0.03). Overall revision rates were not significantly different between the groups (3.5% vs. 4.5%, P = 1.00). Early surgical complications occurred in 6.8% of the frameless stereotaxy group and 1.8% of the fluoroscopy group (P = 0.25). CONCLUSIONS: Ommaya reservoirs can be placed accurately using different methods. Although there are slight differences between fluoroscopy and frameless stereotaxy in quantitative accuracy and procedure time, there is no significant advantage of 1 method over the other when evaluating revision or complication rates. Technique familiarity and surgeon preference may dictate the preferred procedure.

Utility of Neuronavigation in Intracranial Meningioma Resection: A Single-Center Retrospective Study.

OBJECTIVE: In this study, we validate the utility of navigation in intracranial meningioma excision and evaluate the effectiveness of image guidance surgery based on clinical outcome, extent of resection, and recurrence-free survival (RFS). METHODS: Information related to clinical history, use of neuronavigation, neuroimaging, microsurgical dissection, and outcomes of 517 consecutive cases with meningiomas between January 1995 and June 2015 was collected retrospectively. A Cox proportional hazards regression model was used to determine independent predictors of RFS. RESULTS: In this study, overall recurrence rate after tumor excision with or without neuronavigation was 17.7% and 31.2%, respectively (P = 0.03). Based on neuronavigation use, RFS of the patients with meningiomas in different locations also varied significantly (skull base; with, 110 months vs. without, 157 months; P = 0.02). The median RFS for patients operated on with or without use of neuronavigation during resection of tumors was 167 and 97 months, respectively, (log-rank P =0.0001). In Cox regression multivariate analysis, use of neuronavigation (P = 0.0001), gross total resection (Simpson grade I-II; P = 0.001), and World Health Organization grade I tumor (P = 0.0001) were revealed as significant predictors of RFS. In addition, mean blood loss (P = 0.005) and average length of stay (P = 0.008) in the hospital were significantly reduced and performance status was improved using neuronavigation during resection of meningiomas. CONCLUSIONS: Interactive surgical navigation is a useful tool in the operative management of intracranial meningiomas to decrease recurrence rate, blood loss, and length of stay, and to improve RFS and performance status. Therefore, use of neuronavigation should be ensured during resection of intracranial meningiomas.

Use of frameless neuronavigation for bedside placement of external ventricular catheters.

Neuronavigation for placement of ventricular catheters has been described. At our institution, electromagnetic neuronavigation is frequently utilized for difficult ventricular catheter placement. In patients who develop a trapped ventricle as a result of an intraparenchymal or intraventricular mass lesion, successful catheter placement may be difficult, as the location and trajectory are unfamiliar. The authors report their experience using electromagnetic neuronavigation for bedside placement of external ventricular catheters in patients with trapped ventricles. The technique for bedside placement of external ventricular catheters utilizing electromagnetic neuronavigation is reviewed. The benefits of this technique and those patients in whom it may be most useful are discussed. Utilization of bedside electromagnetic neuronavigation for placement of difficult external ventricular catheters into trapped ventricles is an option for accurate navigated catheter placement. Bedside electromagnetic neuronavigation offers accurate catheter placement in awake patients. This technique may be utilized in patients with high perioperative risk factors as it does not require general anesthesia. The procedure is well tolerated as it does not require rigid head fixation.

Endoscopic and keyhole endoscope-assisted neurosurgical approaches: a qualitative survey on technical challenges and technological solutions.

INTRODUCTION: The literature reflects a resurgence of interest in endoscopic and keyhole endoscope-assisted neurosurgical approaches as alternatives to conventional microsurgical approaches in carefully selected cases. The aim of this study was to assess the technical challenges of neuroendoscopy, and the scope for technological innovations to overcome these barriers. MATERIALS AND METHODS: All full members of the Society of British Neurosurgeons (SBNS) were electronically invited to participate in an online survey. The open-ended structured survey asked three questions; firstly, whether the surgeon presently utilises or has experience with endoscopic or endoscope-assisted approaches; secondly, what they consider to be the major technical barriers to adopting such approaches; and thirdly, what technological advances they foresee improving safety and efficacy in the field. Responses were subjected to a qualitative research method of multi-rater emergent theme analysis. RESULTS: Three clear themes emerged: 1) surgical approach and better integration with image-guidance systems (20%), 2) intra-operative visualisation and improvements in neuroendoscopy (49%), and 3) surgical manipulation and improvements in instruments (74%). DISCUSSION: The analysis of responses to our open-ended survey revealed that although opinion was varied three major themes could be identified. Emerging technological advances such as augmented reality, high-definition stereo-endoscopy, and robotic joint-wristed instruments may help overcome the technical difficulties associated with neuroendoscopic approaches. CONCLUSIONS: Results of this qualitative survey provide consensus amongst the technology end-user community such that unambiguous goals and priorities may be defined. Systems integrating these advances could improve the safety and efficacy of endoscopic and endoscope-assisted neurosurgical approaches.

Treatment results of glioblastoma during the last 30 years in a single institute.

Treatment results of glioblastoma (GB) during the last 30 years in Tohoku University were analyzed to identify any improvements in patient outcome in all 332 histologically proven cases of newly diagnosed GB treated consecutively in our department between 1982 and 2011. These 30 years was divided into 5 treatment eras, Group 1 (1982-1988, without preoperative evaluation by magnetic resonance [MR] imaging, n = 46), Group 2 (1989-1996, with preoperative MR imaging, n = 41), Group 3 (1997-1999, additionally underwent intraoperative functional brain mapping and neuronavigation system, n = 38), Group 4 (2000-August 2006, underwent 30 Gy of whole brain radiation followed by 30 Gy of extended local accelerated hyperfractionated radiation therapy, n = 96), and Group 5 (September 2006-2011, adjuvant usage of temozolomide [TMZ], n = 111). Overall survival (OS) was calculated from the date of surgery to the death from any cause. The median survival time/2-year OS/5-year OS of Groups 1 to 5 were 10.7 months/10.9%/0%, 17.3 months/26.2%/6.9%, 15.9 months/23.7%/5.3%, 20.1 months/34.8%/15.5%, and 20.9 months/45.5%/19.7%. The prognosis for patients with GB improved significantly after the introduction of MR imaging. Younger GB, defined as patients aged below 60 years, or total tumor resection with all ages in Group 5 had 5-year 0S of 31.0% and 30.1%, respectively. The prognosis of GB was improved significantly after the introduction of TMZ for elderly GB, recursive partitioning analysis class 5, or totally resected GB. Introduction of MR imaging and TMZ, and total resection of the tumor were important in the improvement of outcome for patients with GB.

Intraventricular and skull base neuroendoscopy in 2012: a global survey of usage patterns and the role of intraoperative neuronavigation.

BACKGROUND: During the past decade, endoscopic intraventricular and skull base operations have become widely used for a variety of evolving indications. A global survey of practicing endoscopic neurosurgeons was performed to characterize patterns of usage regarding endoscopy equipment, instrumentation, and the indications for using image-guided surgery systems (IGSs). METHODS: An online survey consisting of 8 questions was completed by 235 neurosurgeons with endoscopic surgical experience. Responses were entered into a database and subsequently analyzed. RESULTS: The median number of operations performed per year by intraventricular and skull base endoscopic surgeons was 27 and 25, respectively. Data regarding endoscopic equipment brand, diameter, and length are presented. The most commonly reported indications for IGSs during intraventricular endoscopic surgery were tumor biopsy/resection, intraventricular cyst fenestration, septostomy/pellucidotomy, endoscopic third ventriculostomy, and aqueductal stent placement. Intraventricular surgeons reported using IGSs for all cases in 16.6% and never in 24.4%. Overall, endoscopic skull base surgeons reported using IGSs for all cases in 23.9% and never in 18.9%. The most commonly reported indications for IGSs during endoscopic skull base operations were complex sinus/skull base anatomy, extended approaches, and reoperation. CONCLUSIONS: Many variations and permutations for performing intraventricular and skull base endoscopic surgery exist worldwide. Much can be learned by studying the patterns and indications for using various types of equipment and operative adjuncts such as IGSs.

Worldwide survey on the use of navigation in spine surgery.

OBJECTIVE: Computer-assisted surgery (CAS) can improve the accuracy of screw placement and decrease radiation exposure, yet this is not widely accepted among spine surgeons. The current viewpoint of spine surgeons on navigation in their everyday practice is an important issue that has not been studied. A survey-based study assessed opinions on CAS to describe the current global attitudes of surgeons on the use of navigation in spine surgery. METHODS: A 12-item questionnaire focusing on the number and type of surgical cases, the type of equipment available, and general opinions toward CAS was distributed to 3348 AOSpine surgeons (a specialty group within the AO [Arbeitsgemeinschaft für Osteosynthesefragen] Foundation). Latent class analysis was used to investigate the existence of specific groups based on the respondent opinion profiles. RESULTS: A response rate of 20% was recorded. Despite a widespread distribution of navigation systems in North America and Europe, only 11% of surgeons use it routinely. High-volume procedure surgeons, neurological surgeons, and surgeons with a busy minimal invasive surgery practice are more likely to use CAS. "Routine users" consider the accuracy, potential of facilitating complex surgery, and reduction in radiation exposure as the main advantages. The lack of equipment, inadequate training, and high costs are the main reasons that "nonusers" do not use CAS. CONCLUSIONS: Spine surgeons acknowledge the value of CAS, yet current systems do not meet their expectations in terms of ease of use and integration into the surgical work flow. To increase its use, CAS has to become more cost efficient and scientific data are needed to clarify its potential benefits.

Neuronavigational neuroendoscopy--to be or not to be? An international pilot questionnaire-based study.

OBJECTIVE: The almost age-old neuroendoscopy (NE) and neuronavigation (NN) in its twenties independently and indisputably have proved their high value as neurosurgical armamentarium and became even indispensable in some pathologies. However, nowadays the effectiveness of their simultaneous and combined application still is a matter of debate. The purpose of our pilot international, questionnaire-based survey was to assess the position of the opinion leaders in the field of neuroendoscopy worldwide toward the neuronavigational neuroendoscopy (NNNE). METHODS: Within 3 months, a questionnaire with 17 questions was emailed repeatedly to 55 leading academic neuroendoscopic neurosurgeons from 50 institutions in 24 countries. The questionnaire covered aspects of personal and institutional experience in NE, NN, and NNNE, the most frequently treated pathologies by NNNE as well as inquiring the neurosurgeons' opinion for the importance and future of NNNE. RESULTS: Forty-one questionnaires were returned (response rate = 74.6%). Six questionnaires were excluded because of incomplete or incorrect answers, leaving in the survey 35 respondents from 35 institutions in 18 countries. The less experienced neurosurgeons rely in higher degree on NNNE. Most frequently, NNNE is performed for hydrocephalus (procedures other than third ventriculostomy), transsphenoidal surgery, tumor biopsy, and cyst fenestration. Regardless their neurosurgical and NE experience, more than 75% of the respondents state that NNNE extends the range of neuroendoscopic procedures in their neurosurgical departments. CONCLUSION: NNNE represents a valuable operative technique with excellent future prospects. NNNE extends the range of neuroendoscopic procedures, transforming some number of patients from "nonoperable" neuroendoscopically to suitable for neuroendoscopy.

[First intraoperative magnetic resonance imaging in a Spanish hospital of the public healthcare system: initial experience, feasibility and difficulties in our environment]. / Implantación de la primera resonancia magnética intraoperatoria en un hospital de la red sanitaria pública española: experiencia inicial, viabilidad y dificultades en nuestro entorno.

OBJECTIVE: Intraoperative MRI is considered the gold standard among all intraoperative imaging technologies currently available. Its main indication is in the intraoperative detection of residual disease during tumour resections. We present our initial experience with the first intraoperative low-field MRI in a Spanish hospital of the public healthcare system. We evaluate its usefulness and accuracy to detect residual tumours and compare its intraoperative results with images obtained postoperatively using conventional high-field devices. MATERIAL AND METHODS: We retrospectively reviewed the first 21 patients operated on the aid of this technology. Maximal safe resection was the surgical goal in all cases. Surgeries were performed using conventional instrumentation and the required assistance in each case. RESULTS: The mean number of intraoperative studies was 2.3 per procedure (range: 2 to 4). Intraoperative studies proved that the surgical goal had been achieved in 15 patients (71.4%), and detected residual tumour in 6 cases (28.5%). After comparing the last intraoperative image and the postoperative study, 2 cases (9.5%) were considered as "false negatives". CONCLUSIONS: Intraoperative MRI is a safe, reliable and useful tool for guided resection of brain tumours. Low-field devices provide images of sufficient quality at a lower cost; therefore their universalisation seems feasible.

Neuronavigation in cranioorbital neurosurgery - do we really need it?

AIM: The value of neuronavigation in cranioorbital neurosurgery is controversial and relatively unstudied. The aim of this study was to evaluate the application, the usefulness and the reliability of neuronavigation in the neurosurgical treatment of orbital tumours. MATERIAL AND METHODS: A frameless armless infrared-based neuronavigation system was applied in the microsurgical removal of 7 orbital tumors. Image guidance was CT-based in 3 cases, MRI-based in another 3 cases and based on image fusion between CT and MRI image sets in one patient. The extradural fronto-orbital approach was performed in 3 cases, lateral orbitotomy in 2 cases, trans-supraciliar approach in 1 case and inferomedial orbitotomy in 1 case. RESULTS: The surgical procedures were successful in all cases. The procedure-related morbidity and mortality rate in the series was zero. The registration accuracy of the neuronavigation ranged between 1.0 and 1.7 mm, with an average of 1.3 mm. Neuronavigated image guidance was evaluated as useful in all patients. Total tumour removal was achieved in 5 patients and partial tumour excision in 1 case. One patient was only biopsied. CONCLUSION: Neuronavigation is not a substitute for surgical knowledge and experience, but it is a valuable complement with significant intraoperative potential in cranioorbital surgery.

Utilization of intraoperative motor mapping in glioma surgery with high-field intraoperative magnetic resonance imaging.

BACKGROUND/AIMS: The main goal of glioma surgery is to maximize tumor resection while minimizing neurologic injury. The use of high-field intraoperative magnetic resonance imaging (iMRI) and intraoperative cortical mapping (IOM) together enable the surgeon to increase the extent of tumor resection (EOR) and preserve the neurological function. However, there is insufficient evidence to validate the use of IOM with high-field iMRI. METHODS: To study the safety and utility of IOM in a high-field (1.5 T) iMRI suite, we retrospectively studied 38 patients with glioma who underwent surgery with IOM in the iMRI suite. RESULTS: We were able to use IOM in the iMRI suite without any adverse side effects or difficulty. Median EOR was 97%. A new or worsening motor deficit occurred in 14 (37%) patients immediately after the surgery, with 3 (8%) patients exhibiting persistent deficit at 6 months. CONCLUSION: Our findings suggest that IOM can be successfully used in a high-field MRI environment and can help minimize postoperative motor deficit with a higher EOR.

Magnetic resonance neurography and diffusion tensor imaging: origins, history, and clinical impact of the first 50,000 cases with an assessment of efficacy and utility in a prospective 5000-patient study group.

OBJECTIVE: Methods were invented that made it possible to image peripheral nerves in the body and to image neural tracts in the brain. The history, physical basis, and dyadic tensor concept underlying the methods are reviewed. Over a 15-year period, these techniques-magnetic resonance neurography (MRN) and diffusion tensor imaging-were deployed in the clinical and research community in more than 2500 published research reports and applied to approximately 50,000 patients. Within this group, approximately 5000 patients having MRN were carefully tracked on a prospective basis. METHODS: A uniform Neurography imaging methodology was applied in the study group, and all images were reviewed and registered by referral source, clinical indication, efficacy of imaging, and quality. Various classes of image findings were identified and subjected to a variety of small targeted prospective outcome studies. Those findings demonstrated to be clinically significant were then tracked in the larger clinical volume data set. RESULTS: MRN demonstrates mechanical distortion of nerves, hyperintensity consistent with nerve irritation, nerve swelling, discontinuity, relations of nerves to masses, and image features revealing distortion of nerves at entrapment points. These findings are often clinically relevant and warrant full consideration in the diagnostic process. They result in specific pathological diagnoses that are comparable to electrodiagnostic testing in clinical efficacy. A review of clinical outcome studies with diffusion tensor imaging also shows convincing utility. CONCLUSION: MRN and diffusion tensor imaging neural tract imaging have been validated as indispensable clinical diagnostic methods that provide reliable anatomic pathological information. There is no alternative diagnostic method in many situations. With the elapsing of 15 years, tens of thousands of imaging studies, and thousands of publications, these methods should no longer be considered experimental.

Application accuracy of computed tomography-based, image-guided navigation of temporal bone.

OBJECTIVE: Although frameless stereotactic techniques have become indispensable in neurosurgery, their technical complexity requires careful definition and evaluation. Navigation is of particular concern when it is applied to approach a complex, tight surgical area like the temporal bone, where every millimeter is important. Theoretically, the temporal bone is an ideal location in which to use image-guided navigation because its bony construct precludes pre- and intraoperative shift. In this context, the feasibility of using a navigational system is determined by the system's accuracy and by the spatial characteristics of the targets. Literature addressing the accuracy of image guidance techniques in temporal bone surgery is relatively sparse. Accuracy of these systems within the temporal bone is still under investigation. We investigated the application accuracy of computed tomography-based, frameless, image-guided navigation to identify various bony structures in the temporal bone via a retrosigmoid approach. METHODS: In a total of 10 operations, we performed a retrosigmoid approach simulating operative conditions on either side of 5 whole, fresh cadaveric heads. Six titanium microscrews were implanted around the planned craniotomy site as permanent bone reference markers before the surgical procedure. High-resolution computed tomographic scans were obtained (slice thickness, 0.6-mm, contiguous non-overlapping slices; gantry setting, 0 degrees; scan window diameter, 225 mm; pixel size, >0.44 x 0.44). We used a Stryker navigation system (Stryker Instruments, Kalamazoo, MI) for intraoperative navigation. External and internal targets were selected for calculation of navigation accuracy. RESULTS: The system calculated target registration error to be 0.48 +/- 0.21 mm, and the global accuracies (navigation accuracies) were calculated using external over-the-skull and internal targets within the temporal bone. Overall navigation accuracy was 0.91 +/- 0.28 mm; for reaching internal targets within temporal bone, accuracy was 0.94 +/- 0.22 mm; and for external targets, accuracy was 0.83 +/- 0.11 mm. Ninety-five percent of targets could be reached within 1.4 mm of their actual position. CONCLUSION: Using high-resolution computed tomography and bone-implanted reference markers, frameless navigation can be as accurate as frame-based stereotaxy in providing a guide to maximize safe surgical approaches to the temporal bone. Although error-free navigation is not possible with the submillimetric accuracy required by direct anatomic contouring of tiny structures within temporal bone, it still provides a road map to maximize safe surgical exposure.