Giant Olfactory Groove Meningioma-2-Staged Approach: 2-Dimensional Operative Video

Abstract

A 42-yr-old female presented with an olfactory groove meningioma causing progressive vision loss and anosmia. Given the size of the tumor, we opted for a 2-stage surgery: endoscopic endonasal approach (EEA) followed by a craniotomy. Stage I surgery was a transcribriform transplanum EEA using a binostril 4-hand/2 surgeons (ENT and neuro) technique, with the patient positioned supine with the head slightly turned to the right side and tilted to the left, fixed in a 3-pin head clamp, under imaging guidance, in which we drilled out all the affected skull base bone, devascularized and debulked the tumor. Stage II surgery was done through a right frontotemporal craniotomy 2 mo later. The surgery and postoperative period was uneventful with no complications and no need for further reconstruction of the skull base. The patient's vision was normalized. Postoperative magnetic resonance imaging (MRI) confirmed a Simpson Grade 1 resection. The rationale behind this staged approach is that we have found when using a transcranial 1-stage approach the brain edema and necessary retraction required for resection leads to brain injury, oftentimes readily identified in the diffusion-weighted imaging MRI which are associated with different degrees of cognitive impairment. The skull base bone involved is usually not removed via transcranial approaches. Despite requiring a second surgery, this staged approach allows a true total resection (including the affected bone) and in the transcranial stage the brain is more relaxed, with less edema, reducing the need for retraction, which may lead to a better outcome. The patient has given assent and written consent for videos, images, or clinical or genetic information to be published.