Anatomical And Clinical Aplication Study Of A New Method Of Insular Clinical Segmentation And Insula Glioma Classification

Objective:By anatomy and imaging investigation on insular and pyramidal tract (PT), we are discussing to extablish a new method of clinical insular segmentation and insular glioma classification, which can help to estimate postoperative motor dysfunction prognosis and help to provide guidance for protecting PT in operation and reducing the occurance of postoperative moter dysfunction.Methods:To identify anterior inferior insular point (AIIP), anterior superior insular point (ASIP), posterior superior insular point (PSIP), posterior inferior insular point (PIIP) and upper central insular point (UCIP) from anatomy specimens and magnetic resonance images (MRI) and use these five points as landmarks for analyzing the spatial interrelationship between PT and insular, and use them as important points for classification for glioma. In the present study, we used Klingler’s white matter anatomy technique to expose the structures from insular cortex to internal capsue in 6 cadaveric brains and to observe the spatial interrelationship between them. Magnetic resonance images of the PT of 10 healthy volunteers were acquired by using diffusion tensor tractography (DTT). By combining the MRI and anatomy results, we retrospectively analyzed the relationship between the isular and PT. By analyzing the MRI data from 31 insular glioma patients who underwent surgeries in Department of Neurosurgery of Anhui Provincial Hospital and by classifying the glioma, we analyzed the relationship between tumor type and preoperative and postoperative motor functionResults:The 5 insula landmarks in brain specimens and magnetic resonance images were easily identifiable. The connecting line between the UCIP and the PIIP divided the insular into the anteroinferior region and the posterosuperior region. In the posterosuperior region, there is no lenticular nucleus compared with the anteroinferior region. The DTT image displayed that the PT went through the deep area of the posterosuperior part of the insular. We defined the gliomas those lie in anteroinferior region as type I, those lie in posterosuperior region or the whole region as type Ⅱ, and those invasingto genu and posterior limb internal capsuleas as type Ⅲ. The 31 glioma patients were classified into type I with 20 cases, type Ⅱ with 9 cases and type Ⅲ with 2 cases. Among the patients, there were 1 case from type 1,4 cases from type Ⅱ and 2 cases from type Ⅲ were patients with preopertive motor malfunction, and 1 case from type I,2 cases from type II and 2 cases from type Ⅲ.Type I glioma has the least risk of motor malfunction and the postoperative paralysis, while type Ⅱ has the most risk, and type Ⅱ has the risk in between the other two types.Conclusion:The posterosuperior region of the insular, which is divided by the connecting line between the UCIP and the PUP, is near to the PT and is a dangerous area in the operation. Classification of type Ⅰ,Ⅱ,Ⅲ is very useful to estimate the risk of operation and prognosis of motor function and provide guidance for protecting PT in the operation...