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

Treatment of a Patient With Meningioma With Complicated Blood Supply

Meningiomas account for ~30% of primary intracranial tumors, making them the second most common type of brain tumor. Most meningiomas are benign, and surgical resection is curative. By utilizing 3-dimensional slicer technology for multimodal image fusion, a wealth of 3-dimensional anatomic information can be obtained, enabling more effective treatment of meningiomas with complex tumor locations and surrounding structures. Guided by the 3-dimensional structural models, we conducted detailed preoperative planning for 1 case of highly vascularized meningioma and utilized combined surgery for complete tumor removal, effectively avoiding intraoperative bleeding and postoperative complications.

Comparison of Short-Term Surgery Outcomes and Clinical Characteristics Between Elderly and Non-Elderly Patients with Middle Third Parasagittal and Parafalcine Meningiomas

Purpose

This study aims to compare the short-term surgery outcomes of the resection of meningiomas and clinical characteristics between elderly and non-elderly patients.

Patients and Methods

This retrospective study included patients who underwent a resection of middle third parasagittal and parafalcine meningiomas between January 2011 and December 2020. All lesions arise from the middle third of the parafalcine or infiltrate superior sagittal sinus (SSS). The clinical characteristics studied included neurological deficit, peritumoral brain edema (PTBE), SSS invasion, tumor size, and symptoms; perioperative complications, and short-term surgery outcomes including neurological deficit, operative blood loss, postoperative hospitalization duration, and WHO classification were compared.

Results

A total of 43 elderly patients and 63 non-elderly patients were included. Compared with non-elderly patients, elderly patients had larger lesions (P = 0.013) and presented with a larger PTBE (P = 0.019). SSS blockage was identified in 28.57% of elderly patients and 19.57% of non-elderly patients. Compared with non-elderly patients, elderly patients tended to suffer from more aggressive lesions (WHO II/III meningioma 6 vs 3, P = 0.154) and presented with longer postoperative hospital stays (17.25 ± 5.8 vs 13.50 ± 3.8, P = 0.009); conversely, while the non-elderly patients experienced more blood loss (P = 0.022) and had more perioperative reoperations (3 vs 1). No significant difference in neurological deficit was detected between the two groups (P = 0.97). After total tumor resection, patients with neurological deficits in both groups can recover during the follow-up period.

Conclusion

Among the 106 patients with middle third parasagittal and falx meningiomas in our hospital, elderly patients had larger lesions, presented with more severe PTBE, and had longer postoperative hospital stays than younger patients. Conversely, younger patients had more blood loss and serious complications than elderly patients. Postoperative neurological dysfunction in elderly patients was similar to that in middle-aged and young patients.

Preoperative meningioma vascularity index is associated with significantly increased intraoperative blood loss and greater risk of subtotal resection

OBJECTIVE

Surgical recovery of meningiomas relies on a variety of factors, including tumor volume, vascularity, embolization status, and blood loss during excision. Although hypervascular meningiomas can potentially be amendable to embolization, methods for determining optimal vascularity for this procedure are currently lacking. Our group previously established the meningioma vascularity index (MVI) as a marker of tumor vascularity. In this study, we aim to build on our previous work and further examine the relationship between MVI and intraoperative estimated blood loss (EBL).

METHODS

A retrospective data extraction was conducted between August 2010 and October 2019 from patients undergoing craniotomy for meningioma. Of the 85 intracranial meningiomas included, 39 were embolized. Demographic data, extent of resection, embolization status, and EBL were among the extracted variables. Flow void volumes were measured on T2-weighted MRI images using a segmentation software with a voxel-based segmentation method.

RESULTS

MVI was a predictor of EBL within the entire cohort, when controlling for tumor volume (R² adjusted = 0.26; P = 0.027). A high MVI (> 2.01 cm³) was associated with higher likelihood of receiving subtotal resection (STR) (OR 4.07, 95% CI 1.17-14.15; P = 0.035). Although the mean MVI and tumor volume were higher in the embolized cohort (P = 0.009 and P = 0.005), there were no significant differences in EBL, or blood transfusion rates regardless of embolization status.

CONCLUSIONS

MVI may be used as a non-invasive radiological marker to gauge meningioma vascularity, predict EBL, and guide the decision-making process when it comes to embolization and surgical planning.

Meningioma and Other Meningeal Tumors

Meningiomas develop from meningothelial cells and approximately account for more than 30 percent of central nervous system (CNS) tumors. They can occur anywhere in the dura, most often intracranially and at dural reflection sites. Half of the cases are usually at parasagittal/falcine and convexity locations; other common sites are sphenoid ridge, suprasellar, posterior fossa, and olfactory groove. The female-to-male ratio is approximately 2 or 3-1, and the median age at diagnosis is 65 years. Meningiomas are generally extremely slow-growing tumors; many are asymptomatic or paucisymptomatic at diagnosis and are discovered incidentally. Clinical manifestations, when present, are influenced by the tumor site and by the time course over which it develops. Meningiomas are divided into three grades. Grade I represents the vast majority of cases; they are considered typical or benign, although their CNS location can still lead to severe morbidity or mortality, resulting in a reported ten-year net survival of over 80%. Atypical (WHO grade II) meningiomas are considered "intermediate grade" malignancies and represent 5-7% of cases. They show a tendency for recurrence and malignant degeneration with a relevant increase in tumor cell migration and surrounding tissue infiltration; ten-year net survival is reported over 60%. The anaplastic subtype (WHO III) represents only 1-3% of cases, and it is characterized by a poor prognosis (ten-year net survival of 15%). The treatment of choice for these tumors stands on complete microsurgical resection in case the subsequent morbidities are assumed minimal. On the other hand, and in case the tumor is located in critical regions such as the skull base, or the patient may have accompanied comorbidities, or it is aimed to avoid intensive treatment, some other approaches, including stereotactic radiosurgery and radiotherapy, were recommended as safe and effective choices to be considered as a primary treatment option or complementary to surgery. Adjuvant radiosurgery/radiotherapy should be considered in the case of atypical and anaplastic histology, especially when a residual tumor is identifiable in postoperative imaging. A "watchful waiting" strategy appears reasonable for extremely old individuals and those with substantial comorbidities or low-performance status, while there is a reduced threshold for therapeutic intervention for relatively healthy younger individuals due to the expectation that tumor progression will inevitably necessitate proactive treatment. To treat and manage meningioma efficiently, the assessments of both neurosurgeons and radiation oncologists are essential. The possibility of other rarer tumors, including hemangiopericytomas, solitary fibrous tumors, lymphomas, metastases, melanocytic tumors, and fibrous histiocytoma, must be considered when a meningeal lesion is diagnosed, especially because the ideal diagnostic and therapeutic approaches might differ significantly in every tumor type.

A Brief Explanation on Surgical Approaches for Treatment of Different Brain Tumors

The main goal of brain tumor surgery is to achieve gross total tumor resection without postoperative complications and permanent new deficits. However, when the lesion is located close or within eloquent brain areas, cranial nerves, and/or major brain vessels, it is imperative to balance the extent of resection with the risk of harming the patient, by following a so-called maximal safe resection philosophy. This view implies a shift from an approach-guided attitude, in which few standard surgical approaches are used to treat almost all intracranial tumors, to a pathology-guided one, with surgical approaches actually tailored to the specific tumor that has to be treated with specific dedicated pre- and intraoperative tools and techniques. In this chapter, the basic principles of the most commonly used neurosurgical approaches in brain tumors surgery are presented and discussed along with an overview on all available modern tools able to improve intraoperative visualization, extent of resection, and postoperative clinical outcome.

Ambient ms profiling of meningiomas: intraoperative oncometabolite-based monitoring

The primary method of initial treatment of meningiomas is radical neurosurgical intervention. Various methods of intraoperative diagnostics currently in development aim to improve resection efficiency; we focus on methods based on molecular profiling using ambient ionization mass spectrometry. Such methods have been proven effective on various tumors, but the specifics of the molecular structure and the mechanical properties of meningiomas raise the question of applicability of protocols developed for other conditions for this particular task. The study aimed to compare the potential clinical use of three methods of ambient ionization in meningioma sample analysis: spray from tissue, inline cartridge extraction, and touch spherical sampler probe spray. To this end, lipid and metabolic profiles of meningioma tissues removed in the course of planned neurosurgical intervention have been analyzed. It is shown that in clinical practice, the lipid components of the molecular profile are best analyzed using the inline cartridge extraction method, distinguished by its ease of implementation and highest informational value. Analysis of oncometabolites with low molecular mass is optimally performed with the touch spherical sampler probe spray method, which scores high in both sensitivity and mass-spectrometric complex productivity.

Tailored Approach and Multimodal Intraoperative Neuromonitoring in Cerebellopontine Angle Surgery

The cerebellopontine angle (CPA) is a highly complex anatomical compartment consisting of numerous nervous and vascular structures that present mutual and intricate spatial relationships. CPA surgery represents, therefore, a constant challenge for neurosurgeons. Over the years, neurosurgeons have developed and refined several solutions with the aim of maximizing the surgical treatment effects while minimizing the invasiveness and risks for the patient. In this paper, we present our integrated approach to CPA surgery, describing its advantages in treating pathologies in this anatomical district. Our approach incorporates the use of technology, such as neuronavigation, along with advanced and multimodal intraoperative neuromonitoring (IONM) techniques, with the final goal of making this surgery safe and effective.

Microscope-Based Augmented Reality with Intraoperative Computed Tomography-Based Navigation for Resection of Skull Base Meningiomas in Consecutive Series of 39 Patients

Background: The aim of surgery for skull base meningiomas is maximal resection with minimal damage to the involved cranial nerves and cerebral vessels; thus, implementation of technologies for improved orientation in the surgical field, such as neuronavigation and augmented reality (AR), is of interest. Methods: Included in the study were 39 consecutive patients (13 male, 26 female, mean age 64.08 ± 13.5 years) who underwent surgery for skull base meningiomas using microscope-based AR and automatic patient registration using intraoperative computed tomography (iCT). Results: Most common were olfactory meningiomas (6), cavernous sinus (6) and clinoidal (6) meningiomas, meningiomas of the medial (5) and lateral (5) sphenoid wing and meningiomas of the sphenoidal plane (5), followed by suprasellar (4), falcine (1) and middle fossa (1) meningiomas. There were 26 patients (66.6%) who underwent gross total resection (GTR) of the meningioma. Automatic registration applying iCT resulted in high accuracy (target registration error, 0.82 ± 0.37 mm). The effective radiation dose of the registration iCT scans was 0.58 ± 1.05 mSv. AR facilitated orientation in the resection of skull base meningiomas with encasement of cerebral vessels and compression of the optic chiasm, as well as in reoperations, increasing surgeon comfort. No injuries to critical neurovascular structures occurred. Out of 35 patients who lived to follow-up, 33 could ambulate at their last presentation. Conclusion: A microscope-based AR facilitates surgical orientation for resection of skull base meningiomas. Registration accuracy is very high using automatic registration with intraoperative imaging.

Assessment of necessity of neuronavigation in localization of calvarial extra-axial lesions in the setting of limited resources

Background

Neuronavigation is a very beneficial tool in modern neurosurgical practice. However, the neuronavigation is not available in most of the hospitals in our country raising the question about its importance in localizing the calvarial extra-axial lesions and to what extent it is safe to operate without it.

Methods

We studied twenty patients with calvarial extra-axial lesions who underwent surgical interventions. All lesions were preoperatively located with both neuronavigation and the usual linear measurements. Both methods were compared regarding the time consumed to localize the tumor and the accuracy of each method to anticipate the actual center of the tumor.

Results

The mean error of distance between the planned center of the tumor and the actual was 6.50 ± 1.762 mm in conventional method, whereas the error was 3.85 ± 1.309 mm in IGS method. Much more time was consumed during the neuronavigation method including booting, registration, and positioning. A statistically significant difference was found between the mean time passed in the conventional method and IGS method (2.05 ± 0.826, 24.90 ± 1.334, respectively), P-value < 0.001.

Conclusion

In the setting of limited resources, the linear measurement localization method seems to have an accepted accuracy in the localization of calvarial extra-axial lesions and it saves more time than neuronavigation method.

Evaluation of the effect of standard neuronavigation and augmented reality on the integrity of the perifocal structures during a neurosurgical approach

OBJECTIVE

Intracranial minimally invasive procedures imply working in a restricted surgical corridor surrounded by critical structures, such as vessels and cranial nerves. Any damage to them may affect patient outcome. Neuronavigation systems may reduce the risk of such complications. In this study, the authors sought to compare standard neuronavigation (NV) and augmented reality (AR)-guided navigation with respect to the integrity of the perifocal structures during a neurosurgical approach using a novel model imitating intracranial vessels.

METHODS

A custom-made box, containing crisscrossing hard metal wires, a hidden nail at its bottom, and a wooden top, was scanned, fused, and referenced for the purpose of the study. The metal wires and an aneurysm clip applier were connected to a controller, which counted the number of contacts between them. Twenty-three naive participants were asked to 1) use NV to define an optimal entry point on the top, perform the smallest craniotomy possible on the wooden top, and to use a surgical microscope when placing a clip on the nail without touching the metal wires; and 2) use AR to preoperatively define an ideal trajectory, navigate the surgical microscope, and then perform the same task. The primary outcome was the number of contacts made between the metal wires and the clip applier. Secondary outcomes were craniotomy size, and trust in NV and AR to help avoid touching the metal wires, as assessed by a 9-level Likert scale.

RESULTS

The median number of contacts tended to be lower with the use of AR than with NV (AR, median 1 [Q1: 1, Q3: 2]; NV, median 3 [Q1: 1, Q3: 6]; p = 0.074). The size of the target-oriented craniotomy was significantly lower with the use of AR compared with NV (AR, median 4.91 cm2 [Q1: 4.71 cm2, Q3: 7.55 cm2]; and NV, median 9.62 cm2 [Q1: 7.07 cm2; Q3: 13.85 cm2]). Participants had more trust in AR than in NV (the differences posttest minus pretest were mean 0.9 [SD 1.2] and mean -0.3 [SD 0.2], respectively; p < 0.05).

CONCLUSIONS

The results of this study show a trend favoring the use of AR over NV with respect to reducing contact between a clip applier and the perifocal structures during a simulated clipping of an intracranial aneurysm. Target-guided craniotomies were smaller with the use of AR. AR may be used not only to localize surgical targets but also to prevent complications associated with damage to structures encountered during the surgical approach.

Preliminary Application of Three-Dimensional Printing Technique in Preoperative Localization of Meningioma in Primary Hospitals

OBJECTIVE

To explore the preliminary application of three-dimensional (3D) printing technique in preoperative localization of meningiomas in primary hospitals.

PATIENTS AND METHODS

The enrolled subjects were 13 patients in the Department of Neurosurgery, Affiliated Hospital of Binzhou Medical College, Shandong Province between December 2018 and June 2020, including CT or MRI data from eight cases of brain meningiomas and five cases of cerebrospinal meningiomas. The Mimics 17.0 software package was applied to reconstruct the 3D images and print out the 3D guide. The authors placed the 3D printed guide on the surgical area for preoperative tumor location.

RESULTS

The 3D printed guides for all patients were successfully designed and printed out. Simpson grade I resection was performed on all tumors. No significant hematoma, brain edema, or neurological symptoms were observed in the postoperative patients, and the surgical results were good.

CONCLUSIONS

The authors can use 3D printing technology for precise preoperative localization of meningiomas. Grassroots hospitals can also use this technique because of its economic, accurate, and personalized characteristics.

The Impact of Neuronavigation on the Surgical Outcome of Microvascular Decompression for Trigeminal Neuralgia

OBJECTIVE

Microvascular decompression (MVD) is considered the only etiological treatment for drug-resistant trigeminal neuralgia (TN). Nonetheless, despite the recent technological advances, the risks associated with MVD remain non-negligible. The aim of this study was to evaluate the impact of using neuronavigation on the surgical outcomes of patients with TN submitted for MVD.

METHODS

We analyzed 30 consecutive patients (11 men, 19 women) who underwent MVD for TN between January 2019 and December 2019. Patients were divided in 2 groups according to the use of neuronavigation (group A: MVD with neuronavigation; group B: MVD without neuronavigation). The impact of neuronavigation was assessed on the following parameters: craniotomy size, surgical duration, mastoid air cell opening, postoperative cerebrospinal fluid (CSF) leakage and other complications occurrence, and length of hospitalization. The acute pain relief and the Barrow Neurological Institute score at follow-up were used to evaluate the functional outcome.

RESULTS

The craniotomy size, the surgical duration, and the CSF leak incidence were significantly reduced in group A compared with group B (P = 0.0009, P = 0.0369, and P = 0.0406, respectively). The incidence of mastoid air cell opening, and the length of hospitalization were reduced in group A compared with group B, although these differences were not statistically significant. We obtained an acute pain relief in all cases, and the Barrow Neurological Institute score at follow-up was significantly reduced (P < 0.0001).

CONCLUSIONS

Neuronavigation is a useful tool that significantly reduced craniotomy size, surgical duration, and CSF leak incidence in patients with TN submitted for MVD. We advise to routinely implement neuronavigation in this type of surgery.

Evaluation of the precision of operative augmented reality compared to standard neuronavigation using a 3D-printed skull

OBJECTIVE

Augmented reality (AR) in cranial surgery allows direct projection of preregistered overlaid images in real time on the microscope surgical field. In this study, the authors aimed to compare the precision of AR-assisted navigation and standard pointer-based neuronavigation (NV) by using a 3D-printed skull in surgical conditions.

METHODS

A commercial standardized 3D-printed skull was scanned, fused, and referenced with an MR image and a CT scan of a patient with a 2 × 2-mm right frontal sinus defect. The defect was identified, registered, and integrated into NV. The target was physically marked on the 3D-printed skull replicating the right frontal sinus defect. Twenty-six subjects participated, 25 of whom had no prior NV or AR experience and 1 with little AR experience. The subjects were briefly trained in how to use NV, AR, and AR recalibration tools. Participants were asked to do the following: 1) "target the center of the defect in the 3D-printed skull with a navigation pointer, assisted only by NV orientation," and 2) "use the surgical microscope and AR to focus on the center of the projected object" under conventional surgical conditions. For the AR task, the number of recalibrations was recorded. Confidence regarding NV and AR precision were assessed prior to and after the experiment by using a 9-level Likert scale.

RESULTS

The median distance to target was statistically lower for AR than for NV (1 mm [Q1: 1 mm, Q3: 2 mm] vs 3 mm [Q1: 2 mm, Q3: 4 mm] [p < 0.001]). In the AR task, the median number of recalibrations was 4 (Q1: 4, Q3: 4.75). The number of recalibrations was significantly correlated with the precision (Spearman rho: -0.71, p < 0.05). The trust assessment after performing the experiment scored a median of 8 for AR and 5.5 for NV (p < 0.01).

CONCLUSIONS

This study shows for the first time the superiority of AR over NV in terms of precision. AR is easy to use. The number of recalibrations performed using reference structures increases the precision of the navigation. The confidence regarding precision increases with experience.

Image-guided cochlear access by non-invasive registration: a cadaveric feasibility study

Image-guided cochlear implant surgery is expected to reduce volume of mastoidectomy, accelerate recovery, and improve safety. The purpose of this study was to investigate the safety and effectiveness of image-guided cochlear implant surgery by a non-invasive registration method, in a cadaveric study. We developed a visual positioning frame that can utilize the maxillary dentition as a registration tool and completed the tunnels experiment on 5 cadaver specimens (8 cases in total). The accuracy of the entry point and the target point were 0.471 ± 0.276 mm and 0.671 ± 0.268 mm, respectively. The shortest distance from the margin of the tunnel to the facial nerve and the ossicular chain were 0.790 ± 0.709 mm and 1.960 ± 0.630 mm, respectively. All facial nerves, tympanic membranes, and ossicular chains were completely preserved. Using this approach, high accuracy was achieved in this preliminary study, suggesting that the non-invasive registration method can meet the accuracy requirements for cochlear implant surgery. Based on the above accuracy, we speculate that our method can also be applied to neurosurgery, orbitofacial surgery, lateral skull base surgery, and anterior skull base surgery with satisfactory accuracy.

[Use of navigation in skull base surgery]

The review briefly presents the history of development of navigation systems in neurosurgery. The idea of the existing principles underlying the navigation systems used in neurosurgery is given. Currently, the basic principles of navigation are optical and electromagnetic. Studies are presented comparing the accuracy of various navigation systems. Optical navigation demonstrates greater accuracy compared to electromagnetic, but both methods demonstrate a submillimeter error in the experiment. The history of use of navigation in the surgery of the skull base is analyzed in detail, the most relevant areas of use of navigation within the surgery of the skull base are considered: craniofacial reconstruction, endoscopic endonasal surgery, surgery of common tumors of the skull base affecting the infratemporal, pterygopalatine fossa, temporomandibular joint. Indications for the use of navigation, limitations of the methodology are explained.

Image-guided surgery for meningioma

Image-guided surgery (IGS-neuronavigation) has revolutionized the field of neurosurgery over the past few decades. Although commonly used for the diagnosis and resection of intracranial gliomas and metastases, IGS is also useful for meningioma surgery, particularly for accessing deep tumors, creating an optimal craniotomy for superficial lesions, and for showing the location of critical neurovascular structures deep to the tumor in skull base surgery. An additional bonus in meningioma surgery is that so-called brain shift is minimal or nonexistent, allowing for ongoing accurate navigation during the surgical procedure.

Endoscopic transorbital superior eyelid approach: anatomical study from a neurosurgical perspective

OBJECTIVERecent studies have proposed the superior eyelid endoscopic transorbital approach as a new minimally invasive route to access orbital lesions, mostly in otolaryngology and maxillofacial surgeries. The authors undertook this anatomical study in order to contribute a neurosurgical perspective, exploring the anterior and middle cranial fossa areas through this purely endoscopic transorbital trajectory.METHODSAnatomical dissections were performed in 10 human cadaveric heads (20 sides) using 0° and 30° endoscopes. A step-by-step description of the superior eyelid transorbital endoscopic route and surgically oriented classification are provided.RESULTSThe authors' cadaveric prosection of this approach defined 3 modular routes that could be combined. Two corridors using bone removal lateral to the superior and inferior orbital fissures exposed the middle and anterior cranial fossa (lateral orbital corridors to the anterior and middle cranial base) to unveil the temporal pole region, lateral wall of the cavernous sinus, middle cranial fossa floor, and frontobasal area (i.e., orbital and recti gyri of the frontal lobe). Combined, these 2 corridors exposed the lateral aspect of the lesser sphenoid wing with the Sylvian region (combined lateral orbital corridor to the anterior and middle cranial fossa, with lesser sphenoid wing removal). The medial corridor, with extension of bone removal medially to the superior and inferior orbital fissure, afforded exposure of the opticocarotid area (medial orbital corridor to the opticocarotid area).CONCLUSIONSAlong with its minimally invasive nature, the superior eyelid transorbital approach allows good visualization and manipulation of anatomical structures mainly located in the anterior and middle cranial fossae (i.e., lateral to the superior and inferior orbital fissures). The visualization and management of the opticocarotid region medial to the superior orbital fissure are more complex. Further studies are needed to prove clinical applications of this relatively novel surgical pathway.

The Role of Surgery in Meningiomas

PURPOSE OF REVIEW

This review presents the most recent evidences and recommendations in the pre-, intra-, and post-surgical management of patients harboring meningiomas. Due to the increasing relevance of multimodal approaches, in order to preserve patients' neurological function and quality of life (QoL), the role of observation and radiation treatments (as either primary or adjuvant therapy) has also been discussed.

RECENT FINDINGS

Multiple advances in neurosurgery, including the use of the microscope and endoscope, improved preoperative neuroimaging, intraoperative image-guided approaches, and intraoperative neurophysiological monitoring, have extended the neurosurgeon's ability to remove lesions that were previously considered only partially resectable or unresectable, while minimizing morbidity. On the other hand, the preservation of patients' neurological integrity and QoL are increasingly important issues, more than complete tumor resection, for both patients and neurosurgeons. In this setting, stereotactic radiosurgery (SRS) and radiotherapy (RT) may be considered safe and effective alternatives for asymptomatic small- to moderate-sized tumors that demonstrate growth on serial imaging, or in combination with planned subtotal resection (STR) for tumors in critical locations. Data supporting the use of pharmacotherapy in meningiomas are, to date, weak, but the strength of the evidence might improve in the next future with the identification of targetable mutations. Complete microsurgical resection remains the standard of care if it can be achieved with minimal or no morbidity. However, many studies have reported SRS/RT as safe and effective treatments, either as primary approach or as complementary to surgery, especially when dealing with critically located meningiomas (e.g., cranial base) or in patients with comorbidity or wishing to avoid invasive treatments. The management of meningiomas is a field of complementary disciplines: neurosurgeon needs to work closely with radiation oncologists while tailoring the optimal treatment for these patients in order to achieve the best results.

Meningioma Surgery-Are We Making Progress?

BACKGROUND

To study improvements in outcomes after surgery for intracranial meningiomas.

METHODS

We performed a longitudinal observational study comparing 1469 patients operated on for intracranial meningioma in 4 consecutive time frames (1990-1994, 1995-1999, 2000-2004, and 2005-2010).

RESULTS

Median age at surgery was 58.3 years. Median follow-up was 7 years. Patients in later periods were older than in the earlier ones (odds ratio [OR], 1.19 [1.09-1.32]; P < 0.0005), indicating a trend toward operating on more elderly patients. Before 2000, 42%, 32%, 6%, 19%, and 0.3% achieved Simpson grade (SG) I, II, III, IV, and V, respectively, whereas the SG rates were 35%, 37%, 4%, 23%, and 0.9% after 2000 (OR, 1.18 [1.06-1.30]; P < 0.005). The perioperative mortality (OR, 0.65 [0.46-0.91]; P < 0.05) and worsened neurologic outcome rate (OR, 0.70 [0.60-0.83]; P < 0.0001) were significantly lower in later decades, but the 4 surgical periods were similar regarding postoperative infections and hematomas. Retreatment-free survival (RFS) and overall survival (OS) increased significantly over the 4 time frames (P < 0.05 and P < 0.0001, respectively). Multivariate analysis confirmed the improvement of surgical radicality, neurologic outcome, perioperative mortality, OS, and RFS.

CONCLUSIONS

Meningioma surgery as well as patient population changed over the 2 decades considered in this study. We observed higher rates of gross total resection in the later period and the perioperative outcomes improved or were unchanged, which signifies better long-term outcomes, RFS, and OS.

The evolution of cranial meningioma surgery-a single-center 25-year experience

BACKGROUND

There have been major developments in diagnostic and surgical and non-surgical techniques used in the management of meningiomas over last three decades. We set out to describe these changes in a systematic manner.

METHOD

Clinical and radiological data, surgical procedures, complications, and outcome of 817 patients who underwent surgery for primarily diagnosed meningioma between 1991 and 2015 were investigated.

RESULTS

Median age at diagnosis increased significantly from 56 to 59 years (p = .042), while tumor location and preoperative Karnofsky performance status did not change during the observation period. Availability of preoperative MRI increased, and rates of angiography and tumor embolization decreased (p < .001, each). Median duration of total, pre-, and postoperative stay was 13, 2, and 9 days, respectively, and decreased between 1991 and 2015 (p < .001, each). Median incision-suture time varied annually (p < .001) but without becoming clearly longer or shorter during the entire observation period. The use of intraoperative neuronavigation and neuromonitoring increased, while the rates of Simpson grade I and III surgeries decreased (p < .001). Rates of postoperative hemorrhage (p = .997), hydrocephalus (p = .632), and wound infection (p = .126) did not change, while the frequency of early postoperative neurological deficits decreased from 21% between 1991 and 1995 to 13% between 2011 and 2015 (p = .003). During the same time, the rate of surgeries for postoperative cerebrospinal fluid leakage slightly increased from 2 to 3% (p = .049). Within a median follow-up of 62 months, progression was observed in 114 individuals (14%). Progression-free interval did not significantly change during observation period (p > .05). Multivariate analyses confirmed the lack of correlation between year of surgery and tumor relapse (HR: 1.1, p > .05).

CONCLUSIONS

Preoperative diagnosis and surgery of meningiomas have been substantially evolved. Although early neurological outcome has improved, long-term prognosis remains unchanged.

Real-Time Navigation-Guided Drilling Technique for Skull Base Surgery in the Middle and Posterior Fossae

Objective  The usefulness of the bony surface registration method for navigation system image-guided surgery in the lateral or prone position has been reported. This study was performed to evaluate the efficacy of our new real-time navigation-guided drilling technique with bony surface registration for skull base surgery in the middle and posterior fossae. Methods  The study included 29 surgeries for skull base tumors that required drilling of the petrous bone between January 2015 and December 2017 in Shinshu University Hospital. A navigation system was used for drilling of the petrous bone as follows: (1) some labyrinthine structures were marked by color in the source image and superimposed on the navigation image on the workstation preoperatively; (2) bony surface registration was performed with a three-dimensional (3D) skull reconstruction model in the operating room; (3) the petrous bone was drilled under navigation guidance with real-time view-through confirmation of 3D color-marked labyrinthine structures with observation under a microscopic operative view. Results  Real-time identification of some structures in the petrous bone was performed, and adequate and precise drilling of the petrous bone was achieved without the risk of labyrinthine perforation or stress. Using this method, surgeons do not need to alternate their gaze between the surgical field and the navigation screen. Conclusions  Due to the development of bony surface registration, this new technique is useful for drilling petrous bone in the middle and posterior fossa skull base surgeries.

Meningiomas: skull base versus non-skull base

To identify differences between skull base meningiomas (SBM) and non-skull base meningiomas (NSBM). All adult patients (18.0-69.9 years) operated for intracranial meningiomas between 1990 and 2010 at our institution were investigated. Al-Mefty's definition was used to dichotomize tumors into SBM and NSBM. Overall, 1148 consecutive patients were identified. Median age at surgery was 54.2 years [18.1-69.9]. Median follow-up was 7.4 years [0.0-20.9]. There were 562 patients (49%) with SBM and 586 (51%) with NSBM. The two groups were similar with respect to patient age, follow-up time, and number of patients. Overall female-to-male ratio was 2.6:1, but 3.2:1 in SBM and 2.2:1 in NSBM (p < 0.005). With respect to presenting symptoms, SBMs had more often neurological deficits (risk ratio (RR) 1.4; p < 0.0001) and less often seizures (RR 0.4; p < 0.0001). Gross total resections were less frequent in SBM than NSBM (62 vs 84%) (RR 1.3; p < 0.0001). SBMs had a lower risk of WHO grades II and III histology (4.5 vs 9.5%) (RR 0.5; p < 0.001). Worsening of neurological function was more frequent in SBM (21 vs 121%) (RR 1.8; p < 0.001). Retreatment-free survival at 5, 10, and 15 years, respectively, was 80, 70, and 62% for SBM versus 90, 82, and 74% for NSBM (p < 0.0001). Overall survival at 5, 10, and 15 years, respectively, was 93, 85, and 78% for SBM and 96, 91, and 79% for NSBM (p = 0.14). Patients with SBMs had more new-onset neurological deficits and significantly shorter retreatment-free survivals, but this did not adversely affect the overall survival.

Extent of T1+C Intensity Is a Predictor of Blood Loss in Resection of Meningioma

INTRODUCTION

Surgery for meningioma is associated with significant blood loss. Preoperative embolization has been associated with reduction of blood loss and has been noted to decrease intensity on T1 + contrast sequences. We investigate potential relationships between blood loss and the extent of T1 + contrast intensity.

METHODS

Forty-two patients who underwent surgical resection of intracranial meningioma were retrospectively reviewed from August 2009 to May 2016. Clinical data were extracted (age, gender, location of meningioma, grade of meningioma, need for blood transfusion during surgery, preoperative and postoperative hematocrit level, estimated blood loss [EBL], and duration of surgery). Using OsiriX MD, the tumor volume, sinus involvement, peritumoral edema, extent of resection, and T1 index (average T1+C intensity across the tumor normalized to value at basilar artery) were assessed.

RESULTS

With EBL, univariate analysis for gender, tumor volume, and T1 index showed correlations with P value <0.1. A logistic regression to predict EBL <300 mL and ≥300 mL using the 3 variables yielded T1 index (odds ratio [OR], 31.22; 95% confidence interval [CI], 1.14-855.65), gender (OR, 0.17; 95% CI, 0.03-0.96), and tumor volume (OR, 1.05; 95% CI, 1.00-1.10) as significant predictors (all P < 0.05). With duration for surgery, gender, tumor volume, need for blood transfusion, and preoperative hematocrit exhibited P value <0.05; multivariate analysis did not show a significant model.

CONCLUSIONS

Along with gender and tumor volume, extent of T1+C intensity is also an independent predictor of EBL. This finding may be helpful for surgical management of meningioma.

Parasagittal meningiomas: Our surgical experience and the reconstruction technique of the superior sagittal sinus

Background:

The radical resection of parasagittal meningiomas without complications and recurrences is the goal of the neurosurgeon. Nowadays, different managements are proposed. This study describes our surgical technique during the lesional excision and the reconstruction of the superior sagittal sinus (SSS).

Methods:

The total removal (Simpson I and II) of parasagittal meningiomas (WHO grade I and II) was obtained in 75 patients from September 2000 to January 2010. The indocyanine green videoangiography was used before the dural opening and, when necessary, to identify and preserve the cortical veins. The surgery of the SSS was performed in accordance with Sindou's classification, and its reconstruction was achieved through the use of a patch of galea capitis.

Results:

We had no cases of recurrence and thrombotic occlusion of the SSS in 5 years after the reconstruction. No complications were observed in 65 patients, and no cases of mortality were reported. Neurological focal deficits were observed in 5 patients. A brain swelling and a venous infarction were observed in 1 patient. Only one case of thrombotic occlusion was observed. A cerebrospinal fluid leak was observed in 2 patients, and a systemic complication was found in 1 patient.

Conclusion:

Several factors contribute to the success of the parasagittal meningioma surgery. We consider the preservation of the cortical veins to be important, and, when possible, we recommend the reconstruction of the anterior third of the SSS. Our experience has led us to believe that until now surgery is a winning choice if practiced by expert hands.