The surgical challenge of ossified ventrolateral spinal meningiomas: tricks and pearls for managing large ossified meningiomas of the thoracic spine

The authors present an illustrative technical note on microsurgical resection of ventrolateral completely ossified spinal meningiomas (OSMs) and a literature review of the surgical management of calcified spinal meningiomas or OSMs. These tumors are surgically demanding due to their solid consistency, especially when in a ventrolateral location with dislocation of the spinal cord. A challenging case with significant thoracic cord compression and displacement is described. Due to the firm consistency and the ventrolateral localization of the meningioma, a piecemeal resection was necessary. This could have resulted in a free-floating tumor remnant adherent to the spinal cord, impeding safe tumor resection. To avoid such a remnant, an anchoring burr hole was drilled at the border between the spinal cord and the adamantine tumor mass. Then, a microdissector was placed within the anchoring burr hole and the tumor was gently pulled laterally while drilling away the medial parts of the ossified tumor. This procedure was repeated until separation of the tumor from the spinal cord was possible and a gross-total resection (Simpson grade II) was manageable. Throughout the procedure, continuous intraoperative neurophysiological monitoring was performed.