Surgical management of clinoidal meningiomas

Efficiency and safety of optic canal unroofing in tuberculum sellae meningiomas: a meta-analysis and systematic review

Optic canal unroofing (OCU) has gradually become a routine technique for tuberculum sellae meningiomas (TSMs) resection. This meta-analysis aimed to evaluate the efficacy and safety of OCU. A systematic review and meta-analysis of the published literature on this topic from 2003 to 2023 were conducted in accordance with the PRISMA guidelines. Rigorous statistical analysis with a p-value was performed for related change in visual improvement, gross total resection (GTR), visual deterioration, and olfactory nerve damage. The study included 15 articles with 384 patients in whom OCU was performed by the transcranial approach (TCA) or the endoscopic endonasal approach (EEA). Of these, 341 patients had preoperative visual loss, and 266 patients had postoperative visual recovery. The overall rate of visual improvement was 0.803 (95% CI: 0.733-0.874, p < 0.01). The rate of visual improvement in the EEA and TCA groups was 0.884 (95% CI: 0.803-0.965, p < 0.01) and 0.788 (95% CI: 0.700-0.875, p < 0.01). Further analysis of classification shows that the rate of visual improvement in Type I: < 2 cm was 0.889(95% CI: 0.739-0.969), Type II:2-4 cm was 0.844(95% CI: 0.755-0.910), Type III: > 4 cm was 0.500(95% CI: 0.068-0.932) and the total was 0.853(95% CI: 0.779-0.927 p < 0.01) with low heterogeneity of I2 = 20.80%.Twelve studies separately reported GTR with OCU was 293; the rate of GTR was 0.911 (95% CI: 0.848-0.961, p < 0.01). And the rate of GTR in Type I: < 2 cm was 0.933(95% CI: 0.817-0.986), Type II:2-4 cm was 0.880(95% CI: 0.800-0.936), Type III: > 4 cm was 0.600(95% CI: 0.147-0.947). The total was 0.897(95% CI: 0.830-0.965 p < 0.01) with low heterogeneity of I2 = 34.57%. The related complications of OCU were visual deterioration and olfactory nerve damage. Visual decline was reported in nine studies, and the rate was 0.077 (95% CI: 0.041-0.113, p < 0.01). Six studies reported olfactory nerve damage, and the overall rate was 0.054 (95% CI: 0.019-0.090, p < 0.01). OCU could significantly recover preoperative impaired vision and make GTR easier to achieve, which was also a safe and effective technique in TSM.

Prognostic Factors in the Surgery of Clinoidal Meningiomas

INTRODUCTION

Clinoidal meningiomas are currently among the intracranial meningiomas with the greatest neurosurgical complexity, morbidity, and mortality associated with their resection. The worldwide literature has described tumor size (>4 cm³), patient age (>60 years), and invasion of the cavernous sinus as factors associated with a worse clinical outcome following surgery.

METHODS

We describe the series of cases of patients with clinoidal meningiomas who underwent microsurgical resection at our institution between January 2014 and March 2019. The intention was to analyze the multiple preoperative variables, such as the patient's demographic, tumor, and surgical characteristics, such as the Al-Mefty Classification to find a relationship with the patient's clinical outcome during their postoperative follow-up.  Results: Death occurred in 4.8% of the cases. Postoperative morbidity was documented in 42.9%, the most frequent being ophthalmoparesis, followed by worsening of visual acuity, and new onset motor deficits. Radiological characteristics were assessed based on preoperative MRI. The maximum diameter, midline shift, invasion of the cavernous sinus, arterial encasement, and peritumoral edema were evaluated. Average intraoperative bleeding was 1.3 L. The most frequent histological grade was World Health Organization (WHO) grade 1 in 85.6% of the cases. Complete resection was obtained in 52.4% of the cases; 42.8% received fractionated stereotactic radiotherapy after surgery for disease control, and one received radiosurgery. Recurrence occurred in 33.3%. The average follow-up in months was 23.8.  Conclusions: Demographic factors and tumor characteristics in clinoidal meningioma surgery are related to the subtype of meningioma according to the Al-Mefty Classification and impact directly the degree of resection, progression of the disease, and degree of postoperative complications. To achieve maximal resection while minimizing morbidity and mortality, these factors must be considered to decide on an appropriate approach and specific plan for each case.

Extradural Clinoidectomy in Clinoidal Meningiomas: Analysis of the Surgical Technique and Evaluation of the Clinical Outcome

The surgical treatment of clinoidal meningiomas is currently still discussed in the literature. Different surgical approaches have been proposed and evaluated, in multiple studies, in order to improve the surgical outcomes. The aim of this study is to evaluate the advantages of extradural clinoidectomy in the context of tumor removal radicality for visual function improvement. A retrospective analysis was performed on 74 patients—of which 26 patients with clinoidal meningiomas were in group III, according to Al Mefty classification—who underwent surgery at the Policlinico Umberto I Hospital between 2000 and 2019. Further, extradural clinoidectomy was performed on 15 patients (Group A), and 11 patients underwent the pterional approach only (Group B). Additionally, visual impairment was present in all 26 patients before surgery. Next, visual function assessment was performed on all patients, both in presurgery and postsurgery. Radiological follow up was performed at 3 and 6 months, and then every 12 months. Gross Total Resection (GTR) was achieved in 13/15 (86.7%) patients who underwent clinoidectomy, and in 4/11 (36.4%) patients who did not undergo clinoidectomy. Visual function improvement was achieved in 12/15 (80%) patients who underwent clinoidectomy and in 4 of 11 (36.4%) who did not undergo clinoidectomy. According to our study, extradural clinoidectomy is the most suitable method for facilitating the gross total resection of clinoidal meningiomas. Our experience and data suggest that a higher rate of total resection and, subsequently, the best visual outcomes are achieved. Extradural drilling via the anterior clinoid process reveals a wider surgical corridor for meticulous tumor resection.

Surgical management of anterior clinoidal meningiomas: consensus statement on behalf of the EANS skull base section

BACKGROUND

The optimal management of clinoidal meningiomas (CMs) continues to be debated.

METHODS

We constituted a task force comprising the members of the EANS skull base committee along with international experts to derive recommendations for the management of these tumors. The data from the literature along with contemporary practice patterns were discussed within the task force to generate consensual recommendations.

RESULTS AND CONCLUSION

This article represents the consensus opinion of the task force regarding pre-operative evaluations, patient's counselling, surgical classification, and optimal surgical strategy. Although this analysis yielded only Class B evidence and expert opinions, it should guide practitioners in the management of patients with clinoidal meningiomas and might form the basis for future clinical trials.

Stereotactic radiosurgery for clinoid meningiomas: a multi-institutional study

PURPOSE

Resection of clinoid meningiomas can be associated with significant morbidity. Experience with stereotactic radiosurgery (SRS) for clinoid meningiomas remains limited. We studied the safety and effectiveness of SRS for clinoid meningiomas.

METHODS

From twelve institutions participating in the International Radiosurgery Research Foundation, we pooled patients treated with SRS for radiologically suspected or histologically confirmed WHO grade I clinoid meningiomas.

RESULTS

Two hundred seven patients (median age: 56 years) underwent SRS for clinoid meningiomas. Median treatment volume was 8.02 cm³, and 87% of tumors were immediately adjacent to the optic apparatus. The median tumor prescription dose was 12 Gy, and the median maximal dose to the anterior optic apparatus was 8.5 Gy. During a median post-SRS imaging follow-up of 51.1 months, 7% of patients experienced tumor progression. Greater margin SRS dose (HR = 0.700, p = 0.007) and pre-SRS radiotherapy (HR = 0.004, p < 0.001) were independent predictors of better tumor control. During median visual follow-up of 48 months, visual function declined in 8% of patients. Pre-SRS visual deficit (HR = 2.938, p = 0.048) and maximal radiation dose to the optic apparatus of ≥ 10 Gy (HR = 11.297, p = 0.02) independently predicted greater risk of post-SRS visual decline. Four patients experienced new post-SRS cranial nerve V neuropathy.

CONCLUSIONS

SRS allows durable control of clinoid meningiomas and visual preservation in the majority of patients. Greater radiosurgical prescription dose is associated with better tumor control. Radiation dose to the optic apparatus of ≥ 10 Gy and visual impairment before the SRS increase risk of visual deterioration.

How I do it: total resection of a giant sphenoclinoidal meningioma with normalization of near blind vision

BACKGROUND

Resection of giant sphenoclinoidal meningiomas (SCLM) remains difficult. We discuss a patient presenting with right eye near blindness who underwent total removal of a giant SCLM, resulting in normal vision and no recurrence.

METHOD

Utilizing frontotemporal craniotomy, devascularization, debulking, and detachment was achieved. Microdissection of tumor off the optic nerve and carotid perforators was accomplished, resulting in total resection, visual normalization, and no deficits using efficient face-to-face microscope set-up, 2-surgeon 4-hand technique, and double bipolar-suction arrangement.

CONCLUSION

Frontotemporal craniotomy was adequate. Preservation of the optic nerve and carotid artery is key. Meticulous microsurgical techniques and refined instruments are important for success.

Unilateral Subfrontal Approach for Giant Tuberculum Sellae Meningioma: Single Center Experience and Review of the Literature

Background

Microsurgical Transcranial approach (mTCA) is the primary choice for the resection of giant Tuberculum Sellae Meningiomas (TSM). The objective of this study is to explore surgical details of unilateral subfrontal approach.

Methods

Ten patients with giant TSM treated by unilateral subfrontal approach were included from January 2018 to June 2021. Demographic characteristics, surgical data, post-procedure complications and outcomes of patients have been descriptive analyzed, combined with systematic literature review to explore the surgical details and the prognosis of unilateral subfrontal approach.

Results

Ten patients include six male and four females, age range from 35 to 77 years, duration of visual impairment from 1 to 12 months, were all performed unilateral subfrontal approach. Nine patients achieved radical resection (Simpson grades I-II) through post-operative imaging confirmation, and Simpson IV resection was performed in the remaining one due to cavernous sinus invasion. The postoperative visual acuity was improved or maintained in 8 patients. Visual acuity decreased in 2 cases, including 1 case of optic nerve atrophy and the other case of optic canal not opening. Five cases with frontal sinus opened were repaired during the operation and there was no postoperative cerebrospinal fluid leakage or intracranial infection. One patient suffered from postoperative anosmia, one patient developed left limb weakness, but their symptoms have improved in the follow-up.

Conclusion

Summarize the experience of our center and previous literature, unilateral forehead bottom craniotomy is a feasible surgical approach for giant tuberculum sellae meningioma. Intraoperative application of EC glue and pedicled fascia flap to repair the frontal sinus can prevent complications associated with frontal sinus opening. Optic canal unroofing has huge advantage in visual improvement.

Surgical Strategies and Clinical Outcome of Large to Giant Sphenoid Wing Meningiomas: A Case Series Study

Large to giant sphenoid wing meningiomas (SWMs) remain surgically challenging due to frequent vascular encasement and a tendency for tumoral invasion of the cavernous sinus and optic canal. We aimed to study the quality of resection, postoperative clinical evolution, and recurrence rate of large SWMs. This retrospective study enrolled 21 patients who underwent surgery between January 2014 and December 2019 for SWMs > 5 cm in diameter (average 6.3 cm). Tumor association with cerebral edema, extension into the cavernous sinus or optic canal, degree of encasement of the major intracranial arteries, and tumor resection grade were recorded. Cognitive decline was the most common symptom (65% of patients), followed by visual decline (52%). Infiltration of the cavernous sinus and optical canal were identified in five and six patients, respectively. Varying degrees of arterial encasement were seen. Gross total resection was achieved in 67% of patients. Long-term follow-up revealed improvement in 17 patients (81%), deterioration in two patients (9.5%), and one death (4.7%) directly related to the surgical procedure. Seven patients displayed postoperative tumor progression and two required reintervention 3 years post initial surgery. Tumor size, vascular encasement, and skull base invasion mean that, despite technological advancements, surgical results are dependent on surgical strategy and skill. Appropriate microsurgical techniques can adequately solve arterial encasement but tumor progression remains an issue.

A new scoring system for predicting extent of resection in medial sphenoid wing meningiomas based on three-dimensional multimodality fusion imaging

BACKGROUND

Three-dimensional (3D) fusion imaging has been proved to be a promising neurosurgical tool for presurgical evaluation of tumor removal. We aim to develop a scoring system based on this new tool to predict the resection grade of medial sphenoid wing meningiomas (mSWM) intuitively.

METHODS

We included 46 patients treated for mSWM from 2014 to 2019 to evaluate their tumors' location, volume, cavernous sinus involvement, vascular encasement, and bone invasion by 3D multimodality fusion imaging. A scoring system based on the significant parameters detected by statistical analysis was created and evaluated.

RESULTS

The tumor volumes ranged from 0.8 cm³ to 171.9 cm³. A total of 39 (84.8%) patients had arterial involvement. Cavernous sinus (CS) involvement was observed in 23 patients (50.0%) and bone invasion was noted in 10 patients (21.7%). Simpson I resection was achieved in 10 patients (21.7%) and Simpson II resection was achieved in 17 patients (37.0%). Fifteen patients (32.6%) underwent Simpson III resection and 4 patients (8.7%) underwent Simpson IV resections. A scoring system was created. The score ranged from 1 to 10 and the mean score of our patients was 5.3 ± 2.8. Strong positive monotonic correlation existed between the score and resection grade (R_s = 0.772, P < 0.001). The scoring system had good predictive capacity with an accuracy of 69.60%.

CONCLUSIONS

We described a scoring system that enabled neurosurgeons to predict extent of resection and outcomes for mSWM preoperatively with 3D multimodality fusion imaging.

TRIAL REGISTRATION

Retrospectively registered.

Anterior Clinoidal Meningiomas: Meningeal Anatomical Considerations and Surgical Implications

Objective: Surgical removal of anterior clinoidal meningiomas (ACMs) remains a challenge because of its complicated relationship with surrounding meninges, major arteries and cranial nerves. This study aims to define the meningeal structures around the anterior clinoid process (ACP) and its surgical implications.

Methods: Five dry skulls and 19 cadavers were used in the anatomical study. Cadavers were prepared as transverse, coronal, and sagittal plastinated sections, and the meningeal architecture around the ACP was studied with dissecting and confocal microscopies. The database of meningiomas in one single center was retrospectively reviewed, and the patients with ACMs were collected for clinical analysis.

Results: The superior, lateral, medial surfaces, and the tip of ACP were covered by different layers and types of meninges. The ACMs were classified into four main types based on the sites of origin, possible extending pathways following meningeal dura. In the retrospective cohort of 131 ACMs, the percentage of types I, IIa, IIb, III, and IV were 42.0% (55/131), 19.8% (26/131), 9.2% (12/131), 16.8% (22/131), and 12.2% (16/131), respectively. We found that types IIa and I had higher chances for achieving Simpson grade 1–2 resection (92.3 and 85.4%, respectively), followed by type III (54.5%) and type IV (31.3%), while type IIb showed little chance of Simpson grade 1–2 resection. Univariate and multivariate analyses revealed ACM classification and tumor size (<3 cm) to be independent risk factors for achieving more extensive resection.

Conclusion: The meningeal architecture around the ACP may guide and determine the origin and extension of ACMs. The classification based on the meningeal architecture helps to understand surgical anatomy as well as predicting surgical outcomes.

Extended Pterional Approach for Medial Sphenoid Wing Meningioma: A Series of 47 Patients

Background  To describe our operative strategy and analyze its safety and effectiveness for the removal of medial sphenoid wing meningiomas (MSWMs) through the extended pterional approach. Method  We identified 47 patients with MSWMs who were operated using this approach between 1986 and 2016. Medical charts, operative reports, imaging results, and clinical follow-up evaluations were reviewed and retrospectively analyzed. Results  No surgical mortality was observed in this sample. Gross total resection was achieved in 30 (63.8%) patients. Intradural clinoidectomy was performed in 16 (34%) patients. The median length of follow-up was 8.5 years (range, 1-30 years). Conclusion  The extended pterional approach associated with microsurgery techniques provided excellent results for the removal of MSWMs.

Less Invasive Modified Extradural Temporopolar Approach for Paraclinoid Lesions: Operative Technique and Surgical Results in 80 Consecutive Patients

Background  Extradural temporopolar approach for paraclinoid lesions can provide extensive and early exposure of the anterior clinoid process, and complete mobilization and decompression of the optic nerve and internal carotid artery, which can prevent intraoperative neurovascular injury. The present study investigated the usefulness of our less invasive modified technique and discussed its operative nuances. Methods  We retrospectively reviewed medical charts of 80 consecutive patients with neoplastic (21 patients) and vascular lesions (59 patients) who underwent the modified extradural temporopolar approach between September 2009 and March 2014. Results  Preoperative visual acuity worsened in 4 patients (5.0%) and worsening of visual field function occurred in 10 patients (12.5%). Postoperative outcome was good recovery in 71 patients, moderate disability in 6, severe disability in 2, and death in 1 (due to reruptured aneurysm). No operation-related mortality occurred in the series. Conclusion  Less invasive modified extradural temporopolar approach is safe and can be recommended for the surgical treatment of deeply located aneurysms and skull base tumors to reduce the risk of intraoperative optic neurovascular injury.

Anterior Clinoid Metastasis Removed Extradurally: First Case Report

Background  We report a case of isolated metastasis on the anterior clinoid process (ACP) mimicking meningioma.

Clinical Presentation  A 58-year-old male presented with headaches, right-sided visual disturbances, and blurred and double vision. The cause of double vision was partial weakness of the right III nerve, resulting from compression of the nerve by “hypertrophied” tumor-involved right anterior clinoid. Medical history revealed two primary malignant tumors—male breast cancer and prostate cancer (diagnosed 6 and 18 months prior, respectively). The patient was treated with chemotherapy and showed no signs of active disease, recurrence, or metastasis. Postcontrast head magnetic resonance imaging (MRI) showed extra-axial well-bordered enhancing mass measuring 1.6 × 1.1 × 1 × 1 cm (anteroposterior, transverse, and craniocaudal dimensions) on the ACP, resembling a clinoidal meningioma. Extradural clinoidectomy with tumor resection was performed via right orbitozygomatic pretemporal skull base approach. Visual symptoms improved. Follow-up MRI showed no signs of tumor residual or recurrence.

Conclusion  This is the first case report of a metastasis of any kind on ACP. Metastasis should be included as a part of the differential diagnosis of lesions of the anterior clinoid. Extradural clinoidectomy is a safe and effective method in the treatment of these tumors.

Modified extradural temporopolar approach with mini-peeling of dura propria for paraclinoid and/or parasellar tumors: Operative technique and nuances

Background:

Modified extradural temporopolar approach (EDTPA) with mini-peeling of the dura propria can provide extensive exposure of the anterior clinoid process and early exposure, as well as complete mobilization and decompression of the optic nerve and internal carotid artery, which can prevent intraoperative neurovascular injury for paraclinoid and/or parasellar lesions. The present study investigated the usefulness of this modified technique and discusses the operative nuances.

Methods:

We retrospectively reviewed medical charts of 27 consecutive patients with neoplastic paraclinoid and/or parasellar lesions who underwent this modified approach between September 2009 and August 2016.

Results:

Preoperative visual acuity worsened in 2 patients (7.4%), and worsening of visual field function occurred in 2 patients (7.4%). Postoperative outcome was good recovery in 25 patients (92.6%) and moderate disability in 2 (7.4%). No operation-related mortality occurred in the series.

Conclusions:

The modified EDTPA is safe and recommended for surgical treatment of paraclinoid and/or parasellar tumors to reduce the risk of intraoperative optic neurovascular injury.

Predictive factors for surgical outcome in anterior clinoidal meningiomas: Analysis of 59 consecutive surgically treated cases

Despite the advances in the microsurgical technique and anatomical understanding of the anterior and middle skull base, anterior clinoidal meningiomas are still challenging lesions to resect completely and safely due to their intimate relationship with vital neurovascular structures. We report predictive factors for tumor recurrence and postoperative complications based on surgical outcome of patients with anterior clinoidal meningiomas treated at our institution.Fifty-nine consecutive patients with anterior clinoidal meningioma who were surgically treated between March, 1993, and July, 2015, were reviewed retrospectively. For microsurgical tumor removal, orbitocranial or orbitozygomatic (78.0%), extended pterional (15.3%) and subfrontal approach (6.8%) were performed.The median follow-up duration was 54.1 months. Gross total resection (GTR, Simpson's grade I or II) was achieved in 38 patients (64.4%). The overall recurrence rate (new lesion in GTR cases and re-growth in non-GTR cases) was 18.6%. GTR (Hazard ratio [HR] 0.014, 95% confidence interval [CI] 0.001-0.256; P = .004), absence of internal feeder (HR 0.058, 95% CI 0.004-0.759; P = .030) and benign pathology (WHO grade I, HR 0.056, 95% CI 0.005-0.674; P = .023) were independent prognostic factors for recurrence-free. Fourteen patients (23.7%) developed permanent complications. The most common complication was cranial nerve injury (n = 6; 10.2%), followed by postoperative hemorrhage/infarction, hydrocephalus and infection. Larger size (≥ 40 mm) was significant as an independent predictive factor for permanent complication (HR 0.139, 95% CI 0.030-0.653; P = .012). Old age (≥60 years, P = .056) and peritumoral edema (thickness ≥ 5 mm, P = .303) did not reach statistical significance in multivariate analysis.In surgical resection of anterior clinoidal meningiomas, various clinicoradiological factors were related with resection degree, complication, and progression rate. Although our results showed acceptable resection degree and morbidity, mortality, and recurrence rate, compared to the results of past, anterior clinoidal meningioma remain as neurosurgical challenges because of their close contact to critical vascular and neural structures.

Radiosurgical decompression for benign perioptic tumors causing compressive cranial neuropathies: a feasible alternative to microsurgery?

Several studies have reported the efficacy and safety of hypofractionated stereotactic radiosurgery (hSRS) in the treatment of benign perioptic tumors. This study went further and evaluated the feasibility of hSRS in the treatment of those causing compressive cranial neuropathies (CCNs) among perioptic tumors with special consideration of functional improvement. Twenty-six patients with CCNs (CN II = 19; CN III/IV/VI = 9; CN V = 3) caused by perioptic tumors underwent hSRS between 2011 and 2015. hSRS was delivered in five fractions with a median marginal dose of 27.8 Gy (≈14 Gy in a single fraction, assuming an α/β of three) to a tumor volume of 8.2 ± 8.3 cm³. All tumors except one shrank after treatment, with a mean volume decrease of 35 % (range 4-84 %) during the mean follow-up period of 20 months. In 19 patients (38 eyes) with compressive optic neuropathy, vision improved in 55.3 % of eyes (n = 21), was unchanged in 36.8 % (n = 14), and worsened in 7.9 % (n = 3) (2.6 % after excluding two eyes deteriorated due to transient tumor swelling). A higher conformity index (p = 0.034) and volume of the optic apparatus receiving >23.0 Gy (p = 0.019) were associated with greater tumor shrinkage. A greater decrease in tumor volume (p = 0.035) was associated with a better improvement in vision. Ophthalmoplegia and facial hypesthesia improved in six of nine (66.7 %) and three of three (100 %) patients, respectively. There was no newly developed neurological deficit. Decompressive SRS for benign perioptic tumors causing CCN is feasible using hypofractionation, representing a useful alternative to microsurgical resection.

Surgical Resectability of Skull Base Meningiomas

With recent advances in surgical technology such as preoperative imaging, neuro-monitoring, and surgical instruments, the surgical resectability of intracranial meningiomas has increased over the last two decades. This study reviewed clinical articles regarding the surgical treatment of meningiomas to clarify the role of surgical excision, with a focus on skull base meningiomas. We sub-classified clinical articles about skull base meningiomas into two categories (anterior and middle fossa meningiomas; and posterior fossa meningiomas) and reviewed papers in each category. In cases with anterior and middle fossa meningiomas, surgical resectability has reached a sufficient level to maximize functional preservation. In cases of posterior fossa meningioma, however, surgical respectability remains insufficient even with full use of recent surgical modalities. Continuous refining of operative procedures is required to obtain more satisfactory outcomes, especially for posterior fossa meningioma. In addition, recent long-term outcomes of stereotactic radiosurgery (SRS) were acceptable for controlling the skull base meningiomas. Therefore, combination with surgical excision and SRS should be considered in complicated skull base meningiomas.

Direct visualization of improved optic nerve pial vascular supply following tuberculum meningioma resection: case report

Tuberculum sellae meningiomas frequently produce visual loss by direct compression from tumor, constriction of the optic nerve (ON) under the falciform ligament, and/or ON ischemia. The authors hypothesized that changes in visual function after tumor removal may be related to changes in blood supply to the ON that might be seen in the pial circulation at surgery. Indocyanine green (ICG) angiography was used to attempt to document these changes at surgery. The first patient in whom the technique was used had a left-sided, 1.4-cm, tuberculum meningioma. Time-lapse comparison of images was done postsurgery, and the comparison of video images revealed both faster initial filling and earlier complete filling of the ON pial circulation, suggesting improved pial blood flow after surgical decompression. In follow-up the patient had significant improvements in both visual acuity and visual fields function. Intraoperative ICG angiography of the ON can demonstrate measurable changes in pial vascular flow that may be predictive of postoperative visual outcome. The predictive value of this technique during neurosurgical procedures around the optic apparatus warrants further investigation in a larger cohort.

Meningiomas of the Anterior Clinoid Process: Is It Wise to Drill Out the Optic Canal?

Introduction: Meningiomas of the anterior clinoid process are uncommon tumors, acknowledged by most experienced surgeons to be among the most challenging meningiomas to completely remove. In this article, we summarize our institutional experience removing these uncommon and challenging skull base meningiomas.

Methods: We analyzed the clinical outcomes of patients undergoing surgical removal of anterior at our institution over an 18-year period. We characterized the radiographic appearance of these tumors and related tumor features to symptoms and ability to obtain a gross total resection. We also analyzed visual outcomes in these patients, focusing on visual outcomes with and without optic canal unroofing.

Results: We identified 29 patients with anterior clinoid meningiomas who underwent surgical resection at our institution between 1991 and 2007. The median length of follow-up was 7.5 years (range: 2.0 to 18.6 years). Similar to others, we found gross total resection was seldom safely achievable in these patients. Despite this, only 1/20 of patients undergoing subtotal resection without immediate postoperative radiosurgery experienced tumor progression. The optic canal was unroofed in 18/29 patients in this series, while in 11/29 patients it was not. Notably, all five patients experiencing visual improvement underwent optic canal unroofing, while three of four patients experiencing visual worsening did not.

Conclusions:  These data provide some evidence suggesting that unroofing the optic canal in anterior clinoid meningiomas might improve visual outcomes in these patients.

Towards a hypermodern theory of meningioma surgery

In spite of significant improvements in patient outcomes, meningioma surgery continues to be associated with appreciable morbidity and variability in management schemes, suggesting an opportunity for improvement. In this article, we attempt to cross-pollinate our discipline with theoretical concepts and analytic frameworks from the field of cultural studies over the past several decades. We provide an overview of modernist, postmodernist, and hypermodernist thinking, the last of which emphasizes rapid progress, repeated recreation of dogmas, and data-driven decision-making. We subsequently demonstrate how the evolution of these schools of thought can be used to improve the analytic approach to comparative outcomes research in neurosurgery, with meningioma research as a principal example. We contend that with the renaissance of microsurgery and advent of improved technologies in meningioma management over recent years, modernist analytic methods are no longer adequate. Instead, we advocate for a new hypermodern paradigm that provides evidence-based answers to unresolved questions, minimizes unwarranted variability in clinical practice patterns, and provides a system for continuous assessment and reassessment of outcomes in the rapidly evolving environment of contemporary skull base neurosurgery. In particular, we discuss the relevance of historical case series from leading neurosurgeons for clinical decision-making, the value of seeking new data for longstanding clinical questions, the merits of radiosurgery versus open surgery, and the importance of recognizing tumor heterogeneity rather than simply stratifying them based on general characteristics such as tumor location. In turn, we lay a conceptual foundation for improving outcomes research in meningioma surgery.

Surgical techniques for the dissection of encased perforators in giant clinoidal meningiomas

BACKGROUND

Surgical treatment of giant clinoidal meningiomas remains a challenging task for neurosurgeons. Here, we present details of the surgical techniques for the dissection of encased perforators.

METHODS

The dissection of encased perforators is summarized as follows: (1) split the tumor above the encased arteries and perforators; (2) find the entrance and exit points of the perforators, and estimate the running course of the perforators within the tumor; (3) dissect and expose the perforators along the estimated line.

CONCLUSIONS

The surgical techniques described in this article will aid in achieving maximum tumor resection while preserving encased perforators.

Association of morbidity with extent of resection and cavernous sinus invasion in sphenoid wing meningiomas

Sphenoid wing meningiomas (SWMs) typically are histologically benign, insidious lesions, but the propensity of these tumors for local invasion makes disease control very challenging. In this review, we assess whether the degree of resection and extent of cavernous sinus invasion affects morbidity, mortality, and recurrence in patients with SWM. A comprehensive search of the English-language literature was performed. Patients were stratified according to extent of resection and extent of cavernous sinus invasion, and tumor recurrence rate, morbidity, and mortality were analyzed. A total of 23 studies and 131 patients were included. Overall recurrence and surgical mortality rate were 11% and 2%, respectively (average follow-up = 65 months). Cranial nerve III palsy was significantly associated with incompletely versus completely resected SWMs (7 to 0%) as well as meningiomas with cavernous sinus invasion versus no sinus invasion (14 vs. 0%). No significant difference in tumor recurrence rate was noted between these groups. In conclusion, complete excision of SWMs is always recommended whenever possible, but surgeons should acknowledge that there is nonetheless a chance of recurrence and should weigh this against the risk of causing cranial nerve injuries.

Predictive factors for vision recovery after optic nerve decompression for chronic compressive neuropathy: systematic review and meta-analysis

Objectives Surgical optic nerve decompression for chronic compressive neuropathy results in variable success of vision improvement. We sought to determine the effects of various factors using meta-analysis of available literature. Design Systematic review of MEDLINE databases for the period 1990 to 2010. Setting Academic research center. Participants Studies reporting patients with vision loss from chronic compressive neuropathy undergoing surgery. Main outcome measures Vision outcome reported by each study. Odds ratios (ORs) and 95% confidence intervals (CIs) for predictor variables were calculated. Overall odds ratios were then calculated for each factor, adjusting for inter study heterogeneity. Results Seventy-six studies were identified. Factors with a significant odds of improvement were: less severe vision loss (OR 2.31[95% CI = 1.76 to 3.04]), no disc atrophy (OR 2.60 [95% CI = 1.17 to 5.81]), smaller size (OR 1.82 [95% CI = 1.22 to 2.73]), primary tumor resection (not recurrent) (OR 3.08 [95% CI = 1.84 to 5.14]), no cavernous sinus extension (OR 1.88 [95% CI = 1.03 to 3.43]), soft consistency (OR 4.91 [95% CI = 2.27 to 10.63]), presence of arachnoid plane (OR 5.60 [95% CI = 2.08 to 15.07]), and more extensive resection (OR 0.61 [95% CI = 0.4 to 0.93]). Conclusions Ophthalmologic factors and factors directly related to the lesion are most important in determining vision outcome. The decision to perform optic nerve decompression for vision loss should be made based on careful examination of the patient and realistic discussion regarding the probability of improvement.

Giant anterior clinoidal meningiomas: surgical technique and outcomes

OBJECT

Surgery for giant anterior clinoidal meningiomas that invade vital neurovascular structures surrounding the anterior clinoid process is challenging. The authors present their skull base technique for the treatment of giant anterior clinoidal meningiomas, defined here as globular tumors with a maximum diameter of 5 cm or larger, centered around the anterior clinoid process, which is usually hyperostotic.

METHODS

Between 2000 and 2010, the authors performed 23 surgeries in 22 patients with giant anterior clinoidal meningiomas. They used a skull base approach with extradural unroofing of the optic canal, extradural clinoidectomy (Dolenc technique), transdural debulking of the tumor, early optic nerve decompression, and early identification and control of key neurovascular structures.

RESULTS

The mean age at surgery was 53.8 years. The mean tumor diameter was 59.2 mm (range 50-85 mm) with cavernous sinus involvement in 59.1% (13 of 22 patients). The tumor involved the prechiasmatic segment of the optic nerve in all patients, invaded the optic canal in 77.3% (17 of 22 patients), and caused visual impairment in 86.4% (19 of 22 patients). Total resection (Simpson Grade I or II) was achieved in 30.4% of surgeries (7 of 23); subtotal and partial resections were each achieved in 34.8% of surgeries (8 of 23). The main factor precluding total removal was cavernous sinus involvement. There were no deaths. The mean Glasgow Outcome Scale score was 4.8 (median 5) at a mean of 56 months of follow-up. Vision improved in 66.7% (12 of 18 patients) with consecutive neuroophthalmological examinations, was stable in 22.2% (4 of 18), and deteriorated in 11.1% (2 of 18). New deficits in cranial nerve III or IV remained after 8.7% of surgeries (2 of 23).

CONCLUSIONS

This modified surgical protocol has provided both a good extent of resection and a good neurological and visual outcome in patients with giant anterior clinoidal meningiomas.

Intradural endoscope-assisted anterior clinoidectomy: a cadaveric study

OBJECTIVE

The anterior clinoid process (ACP) is critically related to the clinoidal portion of the internal carotid artery (ICA). The deep location of the ACP makes treatment of vascular and neoplastic lesions related to the ACP challenging. Removal of the ACP is advocated to facilitate treatment of such lesions. However injury to the clinoidal ICA remains a potential and dreadful complication of ACP removal. The aim of this study was to demonstrate an endoscopic assisted technique to perform intradural removal of the ACP via a pterional approach with continuous visualization of the clinoidal ICA.

METHODS

Sixteen bilateral pterional dissections were performed in 8 glutaraldehyde embalmed, colored silicone injected, adult cadaveric heads. Using a standard pterional approach, we performed drilling of the ACP in 2 stages. Stage 1 consisted of extradural microscopic removal of the sphenoid ridge so as to gain access to the origin of the ACP. Stage 2, the endoscopic stage, consisted of intradural endoscopic removal of the ACP and mobilization of the clinoidal segment of the ICA. We used 2.7 mm, 0° and 30° angled endoscopes.

RESULTS

In all the specimens we were able to remove the ACP while at the same time continuously visualizing the clinoidal ICA. The exposure of the clinoidal ICA and of adjoining neuro-vascular structures including the intracranial optic nerve was excellent and was accomplished with minimal frontal lobe retraction. Mobilization of the clinoidal ICA led to unhindered exposure of the parasellar region.

CONCLUSIONS

Endoscopic assisted ACP removal with continuous ICA visualization was feasible in our model. Continuous visualization of the clinoidal ICA should theoretically decrease the risk of inadvertent ICA injuries. Clinical studies to validate this laboratory study are necessary.

The molecular profile of microglia under the influence of glioma

Microglia, which contribute substantially to the tumor mass of glioblastoma, have been shown to play an important role in glioma growth and invasion. While a large number of experimental studies on functional attributes of microglia in glioma provide evidence for their tumor-supporting roles, there also exist hints in support of their anti-tumor properties. Microglial activities during glioma progression seem multifaceted. They have been attributed to the receptors expressed on the microglia surface, to glioma-derived molecules that have an effect on microglia, and to the molecules released by microglia in response to their environment under glioma control, which can have autocrine effects. In this paper, the microglia and glioma literature is reviewed. We provide a synopsis of the molecular profile of microglia under the influence of glioma in order to help establish a rational basis for their potential therapeutic use. The ability of microglia precursors to cross the blood-brain barrier makes them an attractive target for the development of novel cell-based treatments of malignant glioma.

Contemporary surgical outcome for skull base meningiomas

Although surgical excision of meningioma and its dural base is the most common primary management, skull base meningiomas are quite different, and contemporary management usually consists of multimodal treatment with the aim of achieving the best possible functional outcome and quality of life (QOL) for these patients. As surgery plays an important role in the treatment of skull base meningiomas, it is crucial for neurosurgeons to appreciate the surgical outcome and QOL after meningioma surgery. Outcome is usually measured for meningiomas in terms of morbidity, mortality, time to recurrence, and QOL. The extent of resection, tumor grade, proliferative markers, and tumor location are significant factors in predicting the surgical outcome. Therefore, we address each of these factors in detail in this review. Advances in recent decades in microsurgical techniques, neuroimaging modalities, neuroanesthesia, and perioperative intensive care have substantially improved the surgical outcome; therefore, most surgical outcomes discussed in this review are cited from contemporary literature (2000 to the present) in order to depict the surgical outcome of contemporary microsurgery.

Sphenoorbital meningioma: surgical technique and outcome

Object

The aim of this study was to describe the surgical technique used for removal of sphenoorbital meningiomas in the authors' practice and to review the operative outcome.

Methods

Review of the senior author's practice between 1994 and 2009 revealed 39 patients (mean age 48 years) eligible for this study. Clinical presentation, surgical technique, postoperative outcome, and follow-up data are presented. Surgical technique is detailed, with an emphasis on aggressive removal consisting of drilling of the hypertrophied sphenoid bone, orbital wall, and anterior clinoid process, followed by tumor removal and a wide resection of the involved dura. A simple dural closure without reconstruction of the orbital roof or the lateral wall of the orbit is also described.

Results

Gross-total resection was achieved in 15 cases (38.5%), near-total resection with small residual in the cavernous sinus or periorbita in 20 cases (51.3%), and subtotal resection in 4 cases (10.3%). Postoperative complications included trigeminal hypesthesia in 9 patients, oculomotor palsy in 3 patients, and seizure in 2 patients. Seven patients had recurrence within the mean follow-up period of 40.7 months. Preoperative visual deficits were present in 21 patients (53.8%). Of these, 14 (66.7%) experienced visual recovery to normal levels postoperatively. Statistical analyses revealed preoperative severe visual deficit and sphenoid bone hypertrophy as an independent risk factor and an independent favorable factor, respectively, for a favorable visual outcome. Proptosis was resolved (≤ 2 mm) in 73.5% of the authors' patients. No patient had postoperative enophthalmos.

Conclusions

In the authors' practice, surgery for sphenoorbital meningiomas consists of resection of the orbital/sphenoid intraosseous, intraorbital, and intradural tumor components. The authors believe that aggressive removal of the orbital/sphenoid intraosseous tumor is critical for a favorable visual outcome and tumor control. Furthermore, satisfactory cosmetic results can be achieved with simple reconstruction techniques as described.

[Paraclinoid region: descriptive anatomy and radiological correlations with MR imaging]

OBJECTIVE

The paraclinoid region has a complex anatomy. The purpose of this study was to depict in details its anatomical landmarks and their radiological translations with magnetic resonance imaging (MRI).

MATERIAL AND METHOD

Ten anatomical specimens (20 paraclinoid regions) were prepared, then dissected and further analyzed with MRI in order to describe their important radio-anatomical structures (dural folds, osseous surfaces, arteries and nerves) along with their course and measurements, and the reference points of the carotid distal dural ring. The paraclinoid MR protocol consisted in a T2 high-resolution sequence with thin and contiguous slices acquired in a coronal (diaphragmatic) and sagittal oblique (carotid) plane. Reproducibility in living subjects was evaluated on 15 patients (30 paraclinoid regions). Statistical comparison was made between laboratory and MR measurements obtained on cadavers.

RESULTS

A detailed description of paraclinoid anatomy and structures was provided. Its landmarks were satisfactorily identified with the dedicated MR protocol. Reproducibility in living subjects was obtained. No statistical difference was found between laboratory and MR measurements.

CONCLUSION

This study provides a precise description of paraclinoid anatomical structures and their radiological correlations. This paraclinoid MR protocol allows locating paraclinoid lesions in comparison with the cavernous sinus roof, which is of paramount importance for the management of paraclinoid carotid artery aneurysms.

Medial sphenoid ridge meningiomas: early and long-term results of surgical removal using the fronto-temporo-orbito-zygomatic approach

BACKGROUND AND PURPOSE

The fronto-temporo-orbito-zygomatic approach (FTOZA) is an alternative to the pte-rional approach in surgical resection of meningiomas of the medial part of the lesser wing of the sphenoid bone. The purpose of this study is to present our results of treatment of these meningiomas using the FTOZA.

MATERIAL AND METHODS

Thirty patients (19 women, 11 men) with a central skull base tumour were included in the study. The neurological status of the patients was assessed before and after surgery as well as at the conclusion of treatment. The approximate volume of the operated tumour, its relation to large blood vessels, cranial nerves and brainstem, as well as consistency and vascularisation were assessed.

RESULTS

The symptom duration ranged from 1 to 36 months (median: 6 months). Impaired visual acuity was the predominant symptom in 27.5% of patients. Less frequent symptoms included paresis/paralysis of the third cranial nerve, headache, psychoorganic syndrome and epilepsy. Approximate volume of the tumours ranged from 5 to 212 mL (median: 63 mL). Total or subtotal resection was achieved in 77% of patients. The postoperative performance status improved in 16.5%, did not change in 52.8% and deteriorated in 26.4% of patients. One (3.3%) patient died after the surgery.

CONCLUSION

The FTOZA is a useful technique for removal of tumours expanding superiorly to the middle cranial fossa base without significant compression of the brain. Ability to remove tumours through the described approach decreases as the degree of infiltration of the clivus increases.

[Vasculature of the distal part of optic nerve]

BACKGROUND/AIM

Vascularisation of the distal, namely intracranial and intracanalicular parts of the optic nerve have not been explained in conventional textbooks of anatomy, while there have been explanations of proximal, that is intraorbital segment. The aim of this research was to study the pattern of arterial supply of the intracranial and intracanalicular part (the distal part) of human optic nerve.

METHODS

The optic nerve and the ophthalmic artery (OA), predominately in their intracranial and intracanalicular parts, were investigated in 25 human specimens by three different methods: macroscopic, stereomicroscopic, and histological observations. Mixture with 10% of India ink and gelatin was injected through the intracranial part of the internal carotid artery, and the most proximal part of the OA. Each optic canal specimen was fixed in formaldehyde and finally paraffin embedded, sectioned, and stained with Masson trichrome, Azan, Toluidin blue, and Van Gieson methods.

RESULTS

OA passed through the optic canal within the dural sheath of the optic nerve. In 44% of our specimens the OA was on the inferomedial side of the optic nerve at the entrance point to the optic canal. OA left the optic canal at its lateral border in the apex of the orbit in 72% of our specimens. The intracanalicular portion of the optic nerve receives arterial blood principally from the intracanalicular part of OA. OA gives one (72% of the specimens) to two branches that supply the intracanalicular part of the optic nerve. Each branch pierces the dura mater from below and then supplies the nerve through the pia mater. These arteries then terminate in a pial vascular network of continuous transverse centripetal arterioles and capillaries that surround each optic nerve. The rich anastomoses with branches of superior hypophyseal artery, from the cranial cavity, which take part in the optic nerve vascularization in its hole length, was observed. There were no intraaxial vessels in the intracranial and intracanalicular parts of the nerve in our specimens.

CONCLUSION

These anatomical data offer important informations for understanding the variety of the pathology in the region of optic canal and orbito-cranial junction, and is also useful for designing operative strategies. This report indicates the delicacy and vulnerability of the intracranial and intracanalicular capillary network to traumatic disruption.

Anterior clinoidal meningiomas: functional outcome after microsurgical resection in a consecutive series of 106 patients

Object

In this study, the authors' goal was to analyze a series of patients treated microsurgically for an anterior clinoid process (ACP) meningioma in regard to long-term functional outcome.

Methods

The authors retrospectively analyzed clinical data in a consecutive series of 106 patients who underwent microsurgical treatment for an ACP meningioma at 2 neurosurgical institutions between 1987 and 2005. The main presenting symptoms of the 84 female and 22 male patients (mean age 56 years) were visual impairment in 54% and headache in 28%. Physical examination revealed decreased visual acuity in 49% and a visual field deficit in 26%. Tumors were primarily resected via a pterional approach. Meningioma extensions invading the cavernous sinus, present in 29% of the patients, were not removed. Complete tumor resection (Simpson Grade I and II) was achieved in 59% of the cases.

Results

Postoperatively, visual acuity improved in 40%, was unchanged in 46%, and deteriorated in 14%. A new oculomotor palsy was observed in 8 patients (8%). Clinical and MR imaging data were available in 95 patients for a mean postsurgical period of 6.9 years (1.5–18 years) and revealed tumor recurrence in 10% and tumor progression after subtotal resection in 38%. Clinical deterioration on long-term follow-up consisting primarily of ophthalmological deficits was observed in 14% of the cases.

Conclusions

Acceptable functional results can be achieved after microsurgical resection of ACP meningiomas; however, long-term treatment remains challenging due to a high tumor recurrence and progression rate.

Surgical management of tuberculum sellae meningioma: Role of selective extradural anterior clinoidectomy

A retrospective analysis of 32 patients with tuberculum sellae meningiomas who underwent surgery via a unilateral pterional approach was performed. A selective extradural anterior clinoidectomy (SEAC) technique was added in 20 patients. All patients had visual dysfunction preoperatively. Macroscopically complete removal with Simpson grade II was performed in 28 patients (87.5%). The postoperative visual function improved in 25 (78.1%), did not change in 3 (9.4%), and worsened in 4 patients (12.5%). The SEAC technique was effective, especially for removal of the tumour extending into the sellae/pituitary stalk (9 patients), the optic canal (4 patients) and hypothalamus (4 patients) with preservation of the visual and endocrinological function. These results were superior to those of surgery without SEAC technique. This technique is therefore recommended for complete resection of the tuberculum sellae meningiomas extending to the surrounding anatomical structures as the SEAC procedure reduces the risk of intraoperative optic nerve injury considerably.

Tuberculum sellae meningiomas: functional outcome in a consecutive series treated microsurgically

OBJECTIVE

The objective of this study was to analyze a series of patients harboring a tuberculum sellae meningioma with regard to clinical presentation and long-term functional outcome.

METHODS

Data in a consecutive series of 62 patients harboring a tuberculum sellae meningioma treated microsurgically between 1990 and 2003 were retrospectively reviewed.

RESULTS

The mean age of the 46 women and 16 men enrolled in the study was 53 years (range = 29-81 years). The presenting symptom was visual compromise in 87.1% of the patients, and examination revealed decreased visual acuity in 79% and impaired visual fields in 64.5% of the patients. In addition, 14.5% of the patients had preoperative hormonal abnormalities. Simpson grades I and II resections, usually via a pterional approach, were achieved in 90.3% of the patients. Postoperatively, vision improved in 53.2%, remained unchanged in 29.8%, and deteriorated in 17.0% of the patients. The intraoperative finding predicting an unfavorable visual outcome was a thin atrophic optic nerve, encasement of the nerve, or tumor adhesion to its undersurface. Of the patients, 12.9% required permanent postoperative hormonal replacement. After a mean follow-up period of 6.0 years (range = 18 months-14 years), 88.7% of the patients resumed normal life activity and 2 recurrent tumors were observed (3.2%) and reoperated.

CONCLUSIONS

Preoperative magnetic resonance imaging provides reliable information with regard to dislocation of critical vascular structures. However, the relationship between optic nerves and tumors (eg, adhesion and encasement) affected postoperative results and can only be fully appreciated during microsurgery. Visual outcome may be improved by preserving the microvasculature supplying the optic apparatus.

Meningothelioma as the predominant histological subtype of midline skull base and spinal meningioma

Object

This study was undertaken to test a hypothesis that meningiomas of the midline skull base and spine are predominantly of the meningothelial histological subtype.

Methods

The cases of 794 consecutive patients who underwent resection for meningioma at the Cleveland Clinic between January 1991 and March 2004 were reviewed retrospectively. The authors analyzed the relationship between the tumors’ histological subtypes and sites of origin in the 731 patients from this group who harbored tumors that were determined to be benign histologically (World Health Organization Grade I).

Meningothelial meningiomas (MMs) accounted for 63.5% (464/731) of the Grade I tumors. The incidence of MM according to the site of origin was as follows: 84.9% (186/219) in the midline skull base, 58.3% (35/60) in the lateral skull base, 48.5% (183/377) in a non–skull base location, and 80% (60/75) in spinal locations. The incidence of MM in the midline skull base and spinal locations were significantly higher than in non–skull base or lateral skull base locations.

Conclusions

Meningiomas of the midline neuraxis are predominantly meningotheliomas. Analysis of the increasingly available data on genetic and topographic characteristics of MMs suggests that they may represent a unique entity, contrary to the prevailing belief that all benign meningiomas are identical tumors.

Ultrasonic bone curettage for optic canal unroofing and anterior clinoidectomy. Technical note

Extradural unroofing of the optic canal and subsequent mobilization of the optic nerve is a useful technique in the surgical treatment of parasellar tumors; however, the drilling procedure itself is associated with the risk of optic nerve damage. A safer technique would certainly be beneficial. The ultrasonic bone curette is a device developed in Japan for safer bone removal. Its use in intradural anterior clinoidectomy and opening of the internal auditory meatus has been reported before. In this article the authors describe their experience in using this device for extradural unroofing of the optic canal in patients with parasellar tumors. Between March 2002 and November 2004, the aforementioned technique was used in the treatment of eight patients with parasellar tumors. After undertaking a frontotemporal craniotomy and orbital osteotomy, an ultrasonic bone curette was used to unroof the optic canal via an epidural approach; in five cases anterior clinoidectomy was added subsequently. Using an ultrasonic bone curette, unroofing of the optic canal was completed safely and required much less expertise than that required for standard drilling. The mortality and major morbidity rates were 0%. The visual function outcome was satisfactory, with the overall visual status improving in all seven patients in whom this symptom was present preoperatively. The ultrasonic bone curette makes the unroofing of the optic canal safer and easier, possibly improving the visual outcome of patients undergoing surgery for parasellar tumors.

Management of meningiomas en plaque of the sphenoid wing

Object

The authors present their findings on growth patterns in a large series of surgically treated meningiomas en plaque of the sphenoid wing.

Methods

A retrospective case analysis was performed in 67 patients (53 of whom were female) harboring meningiomas en plaque originating from the sphenoid wing, who underwent surgery between 1991 and 2002. The standard surgical approach consisted of pterional craniotomy and extradural resection of any infiltrated bone. The intracranial tumor was removed, and the dura mater and bone were reconstructed. The follow-up period ranged from 6 to 118 months (mean 45.7 months).

Total macroscopic resection was achieved in 40 patients. Forty-eight meningiomas extended to the orbital roof and/or the lateral orbital wall, 34 involved the extraconal space, and eight the intraconal space. Fifty-four tumors involved the superior orbital fissure, 46 the optic canal, and 21 the inferior orbital fissure. Twelve tumors infiltrated the cavernous sinus and 27 involved the anterior clinoid process. There were no deaths in this group of patients; the rate of minor morbidity was 11.9% and the rate of major morbidity was 3%. Subtotal resections were performed in 27 patients because there was intraorbital tumor (eight patients), tumor in the cavernous sinus (nine patients), tumor beyond the tentorial notch (three patients), tumor invading the superior orbital fissure (four patients), and tumor of the skull base (three patients). Five patients underwent postoperative three-dimensional conformal radiotherapy, which resulted in stable tumor volume at follow up. Tumor recurrence was identified in seven patients (10.4%) postoperatively (range of follow up 13–47 months).

Conclusions

The goal of surgery is complete tumor removal without morbidity. An exact analysis of tumor growth and its involvement of different structures is mandatory before performing surgery.

Levine-Sekhar grading system for prediction of the extent of resection of cranial base meningiomas revisited: study of 124 cases

INTRODUCTION

Skull base meningiomas comprise an intricate kingdom in neurological surgery. Due to their proximity to critical neurovascular structures, these tumours impose a cumbersome burden on the surgeon regarding surgical intervention and the clinical outcome. Preoperative prediction of the meningioma resectability will help the surgeon seek a rational result from surgery. This study tries to re-examine and promote the Levine-Sekhar (LS) grading system proposed to predict the resectability of basal meningiomas.

PATIENTS AND METHODS

A retrospective study was performed on 124 eligible patients (90 female and 34 male) suffering from cranial base meningioma that had been operated on between April 1996 and February 2003. The patients were classified according to LS and our modified grading systems. The modified grading system deploys six groups of variables: optic apparatus involvement, cavernous sinus neural involvement, facial-auditory involvement, caudal cranial nerve dysfunction, data derived from imaging studies (multiple fossa involvement and/or vessel encasement), and history of previous radiosurgery. Each criterion scores 1 if present and the total score is the sum of scores obtained from the aforementioned criteria.

RESULTS

Amongst 124 patients, 66 (52%) underwent gross total removal of the tumour. Regression and correlation analysis were performed for both LS (r(2) = 0.9683) and our modified grading systems (r(2) = 0.990) to evaluate the relationship of tumour grade versus the proportion of total resection. The correlations were significantly different (P < 0.01).

CONCLUSION

Although the LS grading system is reported to be a good predictor of the extent of tumour resection, we believe that application of the six aforementioned variables will enhance the accuracy of this system, while preserving simplicity and communicability.

Enhanced exposure of carotico-oculomotor triangle following extradural anterior clinoidectomy: a comparative anatomical study

OBJECTIVE

To quantify and compare the carotico-oculomotor triangle (COT) area before and after extradural anterior clinoidectomy (AC).

METHODS

Ten cadaveric heads were dissected bilaterally. Before and after an extradural AC, the following points were measured: (1) the internal carotid artery (ICA) bifurcation to the tip of the anterior clinoid process (ACP) (A) and to the distal dural ring (A'), (2) the ICA bifurcation to the point where the oculomotor nerve becomes obscured by the tentorial fold (B) and to the porus oculomotoris after incision of the tentorial fold (B'), and (3) the tip of the ACP to the point where the oculomotor nerve becomes obscured by the tentorial incisura (C) and from the distal dural ring to the porus oculomotoris (C'). The area of the COT was calculated before and after AC (DeltaABC and DeltaA'B'C', respectively).

RESULTS

The mean values were as follows: A: 9.15 +/- 0.93 mm, A': 13.45 +/- 0.82 mm; B: 7.80 +/- 1.24 mm, B': 9.90 +/- 1.21 mm; C: 7.15 +/- 0.99 mm, C': 9.3 +/- 1.26 mm; DeltaABC: 26.26 +/- 6.05 mm, DeltaA'B'C': 45.06 +/- 8.92 mm.

CONCLUSIONS

Extradural AC enhances the exposure of the COT almost twofold. This increased exposure can be of significant help during resection of lesions of the parasellar and basilar apex regions.

Surgical management of tuberculum sellae meningiomas: involvement of the optic canal and visual outcome

OBJECTIVE

To present a large series of surgically treated tuberculum sellae meningiomas with particular regard to involvement of the optic canal and visual outcome.

METHODS

A retrospective analysis was done on 53 patients (40 female) with meningiomas originating from the tuberculum sellae who underwent surgery between 1991 and 2002. The standard surgical approach consisted of pterional craniotomy. Sixteen meningiomas extended posteriorly onto the diaphragma sella, 29 anteriorly to the planum sphenoidale, and 19 to the anterior clinoid process. Thirty seven tumours involved the optic canal, three bilaterally. Follow up ranged from 6 to 108 months (mean 29.9 months).

RESULTS

Total macroscopic resection was achieved in 48 patients. Median tumour size was 2.6 cm. Postoperatively, visual acuity improved in 20 patients and deteriorated in seven. Preoperative and postoperative visual acuity worsened with increasing duration of preoperative symptoms and with increasing age. Extension into the intraconal space was a negative predictor. However, tumour size did not influence visual acuity. Recurrence occurred in two cases (21 and 69 months postoperatively). Two patients died from causes unrelated to the tumour.

CONCLUSIONS

In the majority of patients with tuberculum sellae meningiomas, total resection may be achieved through a pterional approach with minimal complications.

Extradural anterior clinoidectomy. Technical note

The anterior clinoid process (ACP), located on the skull base, is a relatively small structure, although its removal provides enormous gain in facilitating the management of lesions--either tumors or aneurysms--in the paraclinoid region and upper basilar artery. The extensive surgical field gained contributes to safer exposure of the neurovascular elements in the vicinity while avoiding excessive and hazardous retraction of the brain. In this report the authors present a technically simpler avenue for performing an extradural anterior clinoidectomy after reviewing the anatomy of the ACP and its anatomical variations. Additionally, the original Dolenc procedure and its subseqtient derivatives are compared and contrasted to the authors' simpler and less laborious technique. Different clinical situations in which to use the procedure are described based on the authors' experience from 60 cases (40 aneurysm cases and 20 tumor cases) during a 4-year period.

Surgical management of meningiomas involving the optic nerve sheath

Object. The management of optic nerve sheath meningiomas (ONSMs) remains controversial but includes surgery, radiotherapy, and plain observation. Surgery is often thought to result in postoperative blindness. The authors report on a large series of patients surgically treated for ONSM, with an emphasis on the visual outcome.

Methods. Seventy-three patients with ONSMs who had undergone surgery between 1991 and 2002 were retrospectively analyzed. The standard surgical approach consisted of pterional craniotomy, intradural (54 patients) or extradural (10 patients) unroofing of the optic canal, or a combined procedure (seven patients). Thirty-two tumors demonstrated extension through the optic canal. Twenty-nine tumors reached the chiasm or contralateral side.

Patients with intraorbital flat tumors should undergo radiotherapy instead of surgery. Those with a large intraorbital mass and no useful vision should undergo surgery. Tumors extending intracranially through the optic canal are amenable to decompression of the optic canal and resection of the intracranial portion.

The follow-up period was a mean 45.4 months (range 6–144 months). Ten patients underwent postoperative radiotherapy. Visual acuity was not significantly influenced by surgery but did become worse with a longer duration of preoperative symptoms and a longer follow-up period. A tumor location in the optic canal was another negative factor. Radiotherapy preserved vision in five of 10 cases.

Conclusions. The loss of vision in patients with ONSM is only a matter of time. In patients with good vision the role of radiotherapy becomes more important. Surgery is recommended for intracranial tumors to prevent contralateral extension.

Management of surgical clinoidal meningiomas

Object

Clinoidal meningiomas remain a major neurosurgical challenge. Surgery-related outcome has been less than desirable in the past, and little attention has been directed toward improving visual deficits. The authors advocate a skull base technique for the removal of these difficult tumors and describe its advantages in terms of improving extent of resection and enhancing overall outcome, particularly visual function.

Methods

A retrospective analysis was performed on data obtained in 26 consecutive patients with clinoidal meningiomas (including one patient with hemangiopericytoma) who underwent resection between June 1995 and January 2003. In 24 cases the skull base procedure involved extradural anterior clinoidectomy, optic canal unroofing, and optic sheath opening; in two cases a standard pterional craniotomy was performed. Fourteen of the 26 patients suffered significant preoperative visual deficits. All patients underwent thorough pre- and postoperative ophthalmological evaluations. The follow-up period ranged from 3 to 91 months (mean 42.3 months). Total resection was achieved in 20 patients (77%), and the majority (76.9%) of patients with preoperative visual impairment experienced significant improvement.

Conclusions

With the use of the skull base technique, total resection and excellent visual outcome may be achieved with minimal morbidity in most patients with clinoidal meningiomas.