Endoscopic endonasal approaches to the skull base tumors: minimally-invasive approach with achievement of radicality. Our experience

Objective: to optimize surgical tactic of endoscopic endonasal transsphenoidal (EET) approaches in cases of tumors with intra- and extracranial extension.Material and methods. For the period of 2013–2019, we retrospectively reviewed 39 patients with tumors of intra-extra skull base location or just extracranial extension. Tumor location and pathology: tumors in pterygopalatine fossa (paraganglioma, carcinoma, neurilemmoma, neurofibroma, chondrosarcoma) — 10 (25.6 %), pituitary adenomas with sphenoid sinus and/or parasellar extension — 14 (35.9 %), sphenoid sinus tumors (carcinoma, neurilemmoma, fibrous dysplasia, angiofibroma, esthesioneuroblastoma) — 8 (20.5 %), petroclival tumors — 6 (15.4 %): hemangiopericytoma — 1, clival tumors — 5 (chordoma), sella turcica lesion with posterior clinoid recess extension (osteoma) – 1 (2.5 %). The extended EET approaches used were as follows: EET + transpterygoid approach — 22 (56.4 %) (in 4 (18.1 %) cases transmaxillary approach was additionally used), extended EET + transclival approach — 4 (10.2 %), EET + transcavernous approach — 2 (5.1 %), EET + transethmoidal approach — 11 (28.2 %). In all cases, we used Karl Storz rigid 4mm 18cm with 0 and 30-degree angled optics. The extent of resection was determined based on routine postoperative CT scans performed within 24 hours after surgery. The volume of resection was evaluated using gadolinium. Gross total resection was defined as the resection of 100 % of the target lesion, subtotal resection as less than 100 % volumetric reduction of the lesion on postoperative CT scans. Further follow-up was done in three, six months and 1 year after surgery, then annually by MRI scanning with gadolinium.Results. Gross total resection was achieved in 7 (77.8 %) cases of tumor in pterygopalatine fossa. In cases of pituitary adenomas with Knosp 3, Knosp 4 cavernous sinus extension, gross total resection was achieved in 7 (53.8 %) individuals. Sphenoid sinus tumors were totally removed in 5 (62.5 %) cases. Subtotal resection was achieved in 11 (28.2 %) cases. Partial resection was achieved in 8 (20.5 %) cases. Postoperative complications were observed in 5 (12.1 %) cases.Conclusions Transethmoidal extended endoscopic endonasal approach is sufficient and good to access the anterior wall of the cavernous sinus improving visualization and better removing of cavernous sinus pathology extension. Transpterygoid extended endoscopic endonasal approach provides sufficient visualization of pterygopalatine fossa, petroclival region. Transmaxillary extension allows reaching the subtemporal region