Transcortical approach for insular gliomas: a series of 253 patients

Purpose The object of this study was to identify the distribution characteristics of insular gliomas and evaluate the efficiency of transcortical approach. Methods Insular gliomas patients who underwent transcortical approach for the first time between March 2011 and July 2019 at our institute were analyzed. Results A total of 253 primary insular gliomas patients were enrolled in the study. Of all patients, 176 patients (69.6%) underwent gross total resection, 61 patients (24.1%) underwent subtotal resection and 16 patients (6.3%) underwent partial resection. According to Berger-Sanai classification, the gross total resection rates of different types of insular gliomas were as follows: Zone I (90.1%), zone II (50.0%), zone III (40.0%), zone IV (89.5%), zone I + II (43.5%), zone I + IV (74.6%), zone II + III (44.4%), zone III + IV (41.7%), Giant (34.5%). According to our modified classification, the gross total resection rates were as follows: anterior type (84.9%), posterior type (45.8%), anterior–posterior type (42.9%), giant type (34.5%). After surgery, new limb motor deficit was observed in 28 patients (11.1%), and 5 patients (2.0%) were left long-term limb motor disability. New language impairment occurred in 23 patients (9.1%), and 3 patients (1.2%) were left long-term language disability. The patients were followed up for 1 to 89.2 months (average, 39.9 ± 20.3 months). At the end of follow-up, tumor progression occurred in 98 (38.7%) patients and 71 (28.1%) patients died of their disease. Conclusion This study demonstrated that the maximal safe resection of insular gliomas can be achieved by transcortical approach. Insular gliomas had the characteristic of forward distribution, anterior transcortical approach can provide enough surgical freedom for anterior type of insular gliomas. If anterior tumors can make route to the posterior parts, anterior transcortical approach was also applied to some anterior–posterior and giant types of insular gliomas without resection of excessive brain, which may reduce the incidence of neurological complications.