Classical pterional compared to the extended skull base approach for the removal of clinoidal meningiomas

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.

The factors influencing postoperative efficacy of anterior clinoidal meningioma treatment and an analysis of best-suited surgical strategies

Objective

To explore the influence of the type of anterior clinoidal meningioma on surgical strategy planning, surgical approach selection, and postoperative efficacy.

Patients and methods

We conducted a retrospective analysis of the clinical data of 63 cases, including data on visual function, extent of tumor resection, and postoperative follow-up. Grade I and II approaches were selected according to the type of tumor. A univariate analysis of the factors influencing the extent of tumor resection, postoperative visual function, and postoperative relapse and complications was conducted.

Results

Simpson Grade I–II total resection was seen in 48 cases (76.2%), with an overall relapse/progression rate of 12.7%. The tumor type and texture and the relationship between the tumors and adjacent structures were the main factors influencing total tumor resection (P < 0.01). The overall postoperative visual acuity improvement, stabilization rate, and deterioration rate were 76.2, 15.9, and 7.9%, respectively. Postoperative visual acuity level was significantly correlated with preoperative visual acuity level and tumor type (P < 0.01).

Conclusions

Determining the type of tumor at a preoperative level and whether the optic canal and cavernous sinus are invaded can aid in the planning of detailed individualized surgical strategies.

Management of the skull base invasion in spheno-orbital meningiomas

BACKGROUND

The tumor invasion of the skull base structures is very frequent in spheno-orbital meningiomas. The aim of the present study is to evaluate the invasion rate of skull base structures and the best surgical approach and management.

METHODS

The surgical series of 80 spheno-orbital meningiomas was reviewed. The tumors were classified according to the intraorbital location with respect to the optic nerve axes into three types: I-lateral: II-medial; III-diffuse. The invasion of the orbital apex, optic canal, superior orbital fissure, anterior clinoid, ethmoid-sphenoid sinuses, and infratemporal fossa was evaluated. The rate and extension of involvement of these structures was correlated with the intraorbital location and the surgical approach. The preoperative ophtalmological symptoms and signs and their outcome were also evaluated.

RESULTS

Proptosis was found in 79 patients (97%), variable decrease of the visual function in 47 patients (59%), and deficits of the eye movements in 28(35%). The invasion of the optic canal (74%), superior orbital fissure (65%), anterior clinoid (60%), and orbital apex (59%) was more frequently found, whereas the tumor extension into the ethmoid-sphenoid sinuses (4%) and infratemporal fossa (4%) was rare. Types II and III meningiomas showed significantly higher involvement of the skull base structures than type I ones, which only had 15% invasion of the optic canal. Remission or significant improvement of the visual function occurred postoperatively in 24 among 47 cases (51%), with a higher rate for type I meningiomas vs. other types (p = 0.021, p = 0.019) and worsening in 7 (15%).

CONCLUSIONS

Spheno-orbital meningiomas growing in the lateral orbital compartment show no involvement of the skull base structures excepting the optic canal as compared to those growing medially or diffusely. The surgical resection of tumor invading the skull base structures should be more extensive as possible, but the risk of optic and oculomotor deficits must be avoided.

Extradural anterior clinoidectomy in surgical management of clinoidal meningiomas

Background

Despite the recent advances in skull base surgery, microsurgical techniques, and neuroimaging, yet surgical resection of clinoidal meningiomas is still a major challenge. In this study, we present our institution experience in the surgical treatment of anterior clinoidal meningiomas highlighting the role of extradural anterior clinoidectomy in improving the visual outcome and the extent of tumor resection. This is a prospective observational study conducted on 33 consecutive patients with clinoidal meningiomas. The surgical approach utilized consisted of extradural anterior clinoidectomy, optic canal deroofing with falciform ligament opening in all patients. The primary outcome assessment was visual improvement and secondary outcomes were extent of tumor resection, recurrence, and postoperative complications.

Results

The study included 5 males and 28 females with mean age 49.48 ± 11.41 years. Preoperative visual deficit was present in 30 (90.9%) patients. Optic canal involvement was present in 24 (72.7%) patients, ICA encasement was in 16 (48.5%), and cavernous sinus invasion in 8 (24.2%). Vision improved in 21 patients (70%), while 6 patients (20%) had stationary course and 1 patient (3%) suffered postoperative new visual deterioration. Gross total resection was achieved in 24 patients (72.7%). The main factors precluding total removal were cavernous sinus involvement and ICA encasement. Mortality rate was 6.1%; mean follow-up period was 27 ± 13 months.

Conclusions

In this series, the use of extradural anterior clinoidectomy provided a favorable visual outcome and improved the extent of resection in clinoidal meningioma patients.

Clinoidal meningiomas

Meningiomas that arise at the anterior clinoid process are termed clinoidal meningiomas and are characterized by unique anatomopathologic correlates that result in unique clinical behavior. According to their site of origin, clinoidal meningiomas can be further divided into three subgroups, which also differ in their clinical presentation and surgical outcome. Clinoidal meningiomas are centered on the anterior clinoid process and grow upward with a small pedicle while causing hyperostosis of the anterior clinoid process itself. The optic nerve is frequently compressed and visual symptoms occur early and in most cases. Upon surgical resection, visual symptoms improve in a significant portion of patients. Cavernous sinus invasion is infrequent. With increasing size, however, clinoidal meningiomas tend to invade surrounding neurovascular structures including distal carotid branches, which results in poor surgical outcome. Most clinoidal meningioma cases are managed with surgery where the anterior clinoid process is also removed along with the tumor either with an extradural or an intradural approach. Standard as well as minimal invasive and skull base approaches are advocated by different groups, but the results are comparable. Surgical results are very good in most cases with low mortality and morbidity. Invasion of the internal carotid artery, optic nerve, or distal carotid branches increase the risk of a postoperative residual. Recurrences are observed and usually managed with Gamma-Knife radiosurgery.

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.

Surgical Resection of Clinoidal Meningiomas without Routine Use of Clinoidectomy

OBJECTIVE

Meningiomas of the anterior clinoid process (ACP) present significant surgical challenges given their anatomic relation to critical neurovascular structures. Routine anterior clinoidectomy is often described as a critical step in the resection of these tumors to reduce recurrence and improve visual outcomes. Anterior clinoidectomy, however, is not without risk and its benefits have not been clearly delineated. We present the outcomes of our series of surgically managed ACP meningiomas in which an anterior clinoidectomy was not routinely employed.

METHODS

A retrospective review of all ACP meningiomas operated on between August 1997 and March 2019 was conducted. Patients with a recurrent tumor or with <6 months of follow-up were excluded. Resection was typically carried out via a frontotemporal craniotomy followed by intradural removal of the tumor. Anterior clinoidectomy was only performed if hyperostosis of the ACP caused mass effect on the optic nerve.

RESULTS

Twenty-nine patients were included in this study. Anterior clinoidectomy was performed in 3 patients (10.3%). Gross total resection was achieved in 22 patients (75.9%). Of the 21 patients (72.4%) who presented with visual deficits, vision improved in 18 patients (85.7%) and worsened in 2 (9.5%). Tumor recurrence occurred in 5 patients (17.2%) at a mean follow-up of 64.9 months. Perioperative morbidity was 10.3%. Permanent morbidity and mortality were 6.9% (vision deterioration) and 0%, respectively.

CONCLUSIONS

Resection of ACP meningiomas without routine anterior clinoidectomy minimizes potential risk while achieving gross total resection, recurrence, and visual improvement rates comparable with those in previously reported series.

Anterior Clinoid Metastasis as First Presentation of a Signet Ring Cell Carcinoma: An Intriguing Diagnosis

Background  We report an extremely unusual case of anterior clinoid process (ACP) metastasis as the first presentation of a signet ring cell carcinoma.

Case Description  A 54-year-old female patient presented with right-sided visual disturbances due to optic nerve compression from a computed tomography (CT)-identified right anterior clinoid bone lesion. Contrast-enhanced magnetic resonance imaging showed an extra-axial, well-bordered enhancing mass extending from the right ACP toward the inner lumen of the optic canal. Pterional approach was adopted to remove the lesion and decompress the optic canal. Histological examination demonstrated a metastasis from a signet ring cell carcinoma. Postoperative CT showed near-total resection of the tumor and decompression of the optic canal. Visual defect remained unchanged.

Conclusion  Metastasis should be considered in the differential diagnosis of the ACP lesions. The early suspicion and identification of this extremely rare pathological entity can be helpful for the prompt management of patients, especially in the absence of any other signs of oncological diseases.

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.

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.

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.