The far-lateral approach for foramen magnum meningiomas.

Foramen magnum meningiomas (FMMs) are slow growing, most often intradural and extramedullary tumors that pose significant challenges to the skull base neurosurgeon. The indolent clinical course of FMMs and their insidious onset of symptoms are important factors that contribute to delayed diagnosis and relative large size at the time of presentation. Symptoms are often produced by compression of surrounding structures (such as the medulla oblongata, upper cervical spinal cord, lower cranial nerves, and vertebral artery) within a critically confined space. Since the initial pathological description of a FMM in 1872, various surgical approaches have been described with the aim of achieving radical tumor resection. The surgical treatment of FMMs has evolved considerably over the last 4 decades due to the progress in microsurgical techniques and development of a multitude of skull base approaches. Posterior and posterolateral FMMs can be safely resected via a standard midline suboccipital approach. However, controversy still exits regarding the optimal management of anterior or anterolateral lesions. Independently of technical variations and the degree of bone removal, all modern surgical approaches to the lower clivus and anterior foramen magnum derive from the posterolateral (or far-lateral) craniotomy originally described by Roberto Heros and Bernard George. This paper is a review of the surgical management of FMMs, with emphasis on the far-lateral approach and its variations. Clinical presentation, imaging findings, important neuroanatomical correlations, recurrence rates, and outcomes are discussed.

Development of contrast-induced nephropathy in subarachnoid hemorrhage: a single center perspective.

BACKGROUND AND PURPOSE: The use of iodinated contrast-enhanced imaging studies is increasing in acute cerebrovascular diseases, especially in subarachnoid hemorrhage (SAH). In SAH, such studies are essential for both diagnosis and treatment of the cause and sequela of hemorrhage. These patients are often subjected to multiple contrast studies such as computed tomographic angiography, computed tomographic perfusion, and cerebral angiography. They are also predisposed to intravascular volume depletion as a part of the disease process from cerebral salt wasting (CSW) and as a result of multiple contrast exposure can develop contrast-induced nephropathy (CIN). Data regarding CIN in this population are scarce. We aimed to examine the incidence of CIN in SAH and identify potential associative risk factors. METHODS: We analyzed data from a prospectively collected patient database of patients with SAH admitted to the neurocritical intensive care unit in a single center over a period of 1 year. CIN was defined as an increase in serum creatinine by >1.5 times or >0.3 mg/dl greater than the admission value, or urine output <0.5 ml/kg/h during one 6-h block. RESULTS: In this cohort of 75 patients with SAH who had undergone at least one contrast study, the mean age was 57.3 ± 15.6 years and 70.7% were women. Four percent developed CIN which resolved within 72 h and none required renal replacement therapy or dialysis. Patients older than 75 years (20%, p < 0.05), those with borderline renal function (14.3%, p = 0.26), diabetics (11.1%, p = 0.32), and those with lower recommended "maximum contrast dose" volume (33.3%, p = 0.12) had a trend toward development of CIN, although most were not statistically significant. Twenty-seven patients (36 %) were on 3% hypertonic saline (HTS) for CSW during the contrasted study but none developed CIN. CONCLUSIONS: The incidence of CIN in SAH patients is comparable to previously published reports on non-neurological cohorts. No definite association was noted with any predisposing factors postulated to be responsible for CIN, except for advanced age. Concurrent use of 3% HTS was not associated with CIN in this population.