Abstract
Objectives Foramen magnum meningiomas (FMM) are complex lesions because of their proximity to
the brain stem and posterior cerebrovasculature. The objective of this study is to
report surgical outcomes and complications after resection of FMM.
Methods A retrospective chart review was conducted on patients with FMM from 1998 to 2015.
Univariate logistic regression and recursive partitioning analysis were used to identify
risk factors associated with complications and extent of resection (EOR).
Results We identified 28 patients with FMM. Median follow-up was 5.9 years. Tumors were World
Health Organization grade I (92.9%) or grade II (7.1%). The vertebral artery was completely
encased (25%), partially encased (11%), or not encased (64%). Median size was 11.9
cm3. EOR was gross total (39%) and subtotal (61%). The observed recurrence rate was 4%
(n = 1). There were 38 complications in 12 patients (43%), and 6 patients (21%) had
complications requiring additional surgery. Complications included cerebrospinal fluid
leak/hydrocephalus (n = 7, 25%), weakness (n = 4, 14%), numbness (n = 4, 14%), and cranial nerve deficits: IX, X (n = 4, 14%), XI (n = 2, 7%), XII (n = 5, 18%). Medical complications included pneumonia (n = 1, 4%) and meningitis (n = 1, 4%). Tumor volume greater than 14 cm3 (odds ratio [OR] = 21.7, p = 0.0010), any vertebral artery encasement (OR 6.1, p = 0.0386), and subtotal resection (OR 6.4, p = 0.0398) were significantly associated with complications. Tumor volume greater
than 14 cm3 was also significantly associated with subtotal resection (OR 8.3, p = 0.0201).
Conclusions Resection of FMM carries perioperative morbidity that increases with larger tumor
size. Despite the morbidity, long-term recurrence-free survival is achievable with
maximal safe resection and adjuvant radiation.
Keywords
foramen magnum - meningioma - complications - outcomes - vertebral artery - surgical
technique - approach - management
