Endonasal Endoscopic Anterior Skull Base Surgery for Sinonasal Malignancies: Juntendo’s Experience

Endoscopic sinus surgery is widely accepted as a primary surgical modality for the treatment of inflammation, trauma, benign tumors, and fibro-osseous lesions. Recent advances in instrumentation, surgical navigation, and skull base reconstruction have enabled endoscopic skull base surgery to emerge as a minimally invasive technique for selective cases. The centripetal endonasal technique consists of 5 main steps including i) reduction of the neoplasm volume, ii) centipetal subperiosteal ethmoidal-nasal removal, iii) removal of bone underlying the tumor, iv) removal of the dura, olfactory bulb, and peri-orbit, and v) skull base duraplasty, which enables dissection of the sinonasal tract in several blocks for the radical removal of a malignant neoplasm. We present our experiences of endoscopic endonasal anterior skull base surgery for 5 cases of sinonasal malignancies with relatively long-term follow-ups of from 41 to 122 months. No local recurrence or distant metastasis was observed. There was no cerebrospinal fluid leak after duraplasty or postoperative infection. The use and indications for endoscopic endonasal surgery of sinonasal malignancies involving the anterior skull base have been expanding. Relatively low-grade malignancies such as olfactory neuroblastoma, adenocarcinoma, and chondrosarcoma in selective cases are good indications for endonasal endoscopic approaches.