Endoscopic Endonasal Classification And Surgical Treatment Of Clivus Chordoma

Objective: To investigate a new classification of clivus chordoma suitable for Endoscopic endonasal approach and related surgical treatment.Methods: The records of 55 patients who presented with clivus chordoma treated with Endoscopic endonasal surgery between 2012.5 and 2018.1 were retrospectively reviewed.Based on the scheme of the clivus notochord,involved in tumor growth and skull base anatomical,these lesions was classified as follows:Type I-A(the upper-middle Dorsal epidural type),Type I-B(the upper-middle Dorsal subdural type),Type II(the upper-middle Ventral type),Type III-A(the lower clivus epidural type),Type III-B(the lower clivus subdural type)and Type IV(the paramedian type).Results: Type I-A in 14 cases and Type I-B in 7 cases;Type I chordoma developed from the notochord of dorsum sellae;the main body was located in the dorsal of parting line,mainly involving the upper and middle clivus.Most presented with visual deterioration and diplopia / abduction paralysis.Type II in 10 cases;Type II chordoma developed from the notochord of the ventral basilar fibrocartilage;the main body was located in the ventral of parting line,mainly involving the upper and middle cli vus.Most presented with nasal obstruction and epistaxis.Type III-A in 10 cases and Type III-B in 7 cases;Type III chordoma developed from the lower clivus;the main body was located in the lower slopes.Most presented with dysphagia,headache / dizziness and tongue muscle paralysis.Type IV in 7 cases;mainly involve the paramedian area,most presented with diplopia / abduction paralysis.All patients had the most common headache / dizziness,followed by vision loss and diplopia / abduction disorders.Total resection of clivus chordoma was achieved in 33 cases,subtotal in 18 cases and partial in 4 cases.The total resection rate of recurrent surgery patients was lower than the primary surgery patients(p<0.05).Conclusion: The existing classifications are not suitable for Endoscopic endonasal resection of clival chordoma.According to the origin,growth behavior of clival chordoma,skull base anatomy and surgical experience,we present the new classification,which can guide Endoscopic endonasal resection of clivus chordoma.