The surgical treatment of meningiomas located at the base of the anterior cranial fossa is often challenging, and the evolution of the surgical strategy to resect these tumors parallels the development of craniotomy, and neurosurgery in general, over the past century. Early successful operations to treat these tumors were pioneered by prominent figures such as Sir William Macewen and Francesco Durante. Following these early reports, Harvey Cushing made significant contributions, allowing a better understanding and treatment of meningiomas in general, but particularly those involving the anterior cranial base. Initially, large-sized unilateral or bilateral craniotomies were necessary to approach these deep-seated lesions. Technical advances such as the introduction of electrosurgery, the operating microscope, and refined microsurgical instruments allowed neurosurgeons to perform less invasive surgical procedures with better results. Today, a wide variety of surgical strategies, including endoscopic surgery and radiosurgery, are used to treat these tumors. In this review, the authors trace the evolution of craniotomy for anterior cranial fossa meningiomas.
Saul F. Morales-Valero, Jamie J. Van Gompel, Ioannis Loumiotis and Giuseppe Lanzino
Ioannis Loumiotis, Anne Wagenbach, Robert D. Brown Jr. and Giuseppe Lanzino
The widespread use of imaging techniques for evaluating nonspecific symptoms (vertigo, dizziness, memory concerns, unsteadiness, and the like) and focal neurological symptoms related to cerebrovascular disease has led to increased identification of asymptomatic incidentally discovered unruptured intracranial aneurysms (UIAs). The management of these incidental aneurysms is controversial and many factors need to be considered. The authors describe reasons leading to diagnosis, demographics, and risk factors in a large consecutive series of patients with small incidentally found UIAs.
The authors prospectively evaluated 335 patients harboring 478 small (< 10-mm) UIAs between January 2008 and May 2011. Patients with known aneurysms, possibly symptomatic aneurysms, arteriovenous malformation–related aneurysms, patients with a history of subarachnoid hemorrhage from another aneurysm, and patients harboring extradural aneurysms were excluded from the analysis. Only truly incidental small aneurysms (272 aneurysms in 212 patients) were considered for the present analysis. Data regarding the reason for detection, demographics, location, and presence of potential risk factors for aneurysm formation were prospectively collected.
There were 158 female (74.5%) and 54 male (25.5%) patients whose mean age was 60.6 years (median 62 years). The most common reason for undergoing the imaging study that led to a diagnosis of the aneurysms was evaluation for nonspecific spells and symptoms related to focal cerebrovascular ischemia (43.4%), known/possible intracranial or neck pathology (24%), and headache (16%). The most common location (27%) of the aneurysm was the middle cerebral artery; the second most common (22%) was the paraclinoid internal carotid artery (excluding cavernous sinus aneurysms). Sixty-nine percent of patients were current or prior smokers, 60% had a diagnosis of hypertension, and 23% had one or more relatives with a history of intracranial aneurysms with or without subarachnoid hemorrhage.
Small incidental UIAs are more commonly diagnosed in elderly individuals during imaging performed to investigate ill-defined spells or focal cerebrovascular ischemic symptoms, or during the evaluation of known or probable unrelated intracranial/neck pathology. Hypertension, smoking, and family history of aneurysms are common in this patient population, and the presence of these risk factors has important implications for treatment recommendations. Although paraclinoid aneurysms (excluding intracavernous aneurysms) are uncommon in patients with ruptured intracranial aneurysms, this location is very common in patients with small incidental UIAs.
Ioannis Loumiotis, Robert D. Brown Jr., Roanna Vine, Harry J. Cloft, David F. Kallmes and Giuseppe Lanzino
The management of incidental small unruptured intracranial aneurysms (UIAs) is controversial and many factors need to be considered in the decision-making process. The authors describe a large consecutive series of patients harboring small incidental intracranial aneurysms. Treatment strategy, natural history, complications, and short-term outcomes are presented.
Between January 2008 and May 2011, the authors prospectively evaluated 212 patients with 272 small (< 10-mm) incidental aneurysms. Treatment recommendations (observation, endovascular treatment, or surgery), complications of treatment, and short-term outcomes were assessed.
Recommended treatment consisted of observation in 125 patients, endovascular embolization in 64, and surgery in 18. Six patients were excluded from further analysis because they underwent treatment elsewhere. In the observation group, at a mean follow-up of 16.7 months, only 1 patient was moved to the embolization group. Seven (6%) of the 125 patients in the observation group died of causes unrelated to aneurysm. Sixty-five patients underwent 69 embolization procedures. The periprocedural permanent morbidity and mortality rates in patients undergoing endovascular treatment were 1.5% and 1.5%, respectively (overall morbidity and mortality rate 3.0%). In the surgery group no periprocedural complications were observed, although 1 patient did not return to her previous occupation. No aneurysmal rupture was documented in any of the 3 treatment groups during the follow-up period.
A cautious and individualized approach to incidental UIAs is of utmost importance for formulation of a safe and effective treatment algorithm. Invasive treatment (either endovascular or surgery) can be considered in selected younger patients, certain “higher-risk” locations, expanding aneurysms, patients with a family history of aneurysmal hemorrhage, and in those who cannot live their lives knowing that they harbor the UIA. Although the complication rate of invasive treatment is very low, it is not negligible. The study confirms that small incidental UIAs deemed to be not in need of treatment have a very benign short-term natural history, which makes observation a reasonable approach in selected patients.