Dural Tail Sign in the Resection of Ventral Foramen Magnum Meningiomas via a Far Lateral Approach: Surgical Implications

Abstract

To investigate the implications of dural tail sign (DTS) in the tailored far lateral approach for resection of ventral foramen magnum meningiomas (FMMs). Clinical data for 16 patients treated surgically for ventral FMMs over 5 years were reviewed retrospectively. The DTS was positive in 11 cases (68.8%) and negative in 5 cases (31.2%). The most frequent form was a single cranial tail (7 of 11), followed by multiple tails consisting of a cranial tail and a caudal tail (3 of 11), and multiple tails composed of a cranial tail and a contralateral tail (1 of 11). The retrocondylar approach was carried out in 5 cases without DTS characterized by a narrow dural attachment and a partial transcondylar approach in 11 cases with DTS featuring a broad and hypervascular dural attachment. Drilling ranged from approximately one fifth to one third of the condyle with reference to the DTS form and tumor size. Total tumor removal was achieved in 16 patients. Postoperative complications were encountered in 25% of patients, predominantly associated with cranial nerve impairment. Follow-up ranging from 8 to 56 months (mean 24.4 months) showed no tumor recurrence. In addition to tumor dural attachment and tumor size, we propose that DTS should be considered as another factor in planning the surgical approach for ventral FMMs. Differentiation between a positive and negative DTS plays a role in the neurosurgical planning of ventral FMMs. Bone removal is warranted in tumors with DTS, particularly the multiple form with contralateral tails, to facilitate the surgical procedure and achieve a more radical resection.