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 cm), 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.