Anatomic and clinical study on transcallosal-interforniceal approach to third ventricle

Abstract

Objective To explore the microanatomic features of the transcallosal-interforniceal approach, and discuss the value of its clinical application. Methods Fifteen adult cadaveric head specimens were dissected by microsurgical anatomic skills to simulate the procedures of the transcallosal-interforniceal approach. Observation and measurement were performed on related anatomic structures. In clinical, 21 patients with the third ventricle tumors underwent tumor resection via the transcallosal-interforniceal approach. Results Using two points on the cortical surface as references that were located 5 and 7 cm anterior to the central sulcus respectively, mean values of related measurements on P5-foramen of Monro (FM) and P7-FM were obtained as follows: (1) the depth of the interhemispheric fissure was 38.46 and 37.62 ram; (2) the height of the corpus callosum was 7.18 and 7.78 nun; (3) the height of the septum pellucidum was 7.53 and 9.88 mm; (4) the thickness of the fornix was 4.72 and 5.16 mm. Under the operative microscope, the tumors were totally removed in 11 cases,subtotally in 8 cases, and partially in 2 cases. Conclusions The corridor of the transcallosal-interforniceal approach should be limited between the lines of P5-FM and P7-FM. The quantitative information obtained in this study permits the preservation of important anatomic structures in operation, such as the motor strip, genu of the corpus callosum, fornical commissure and anterior commissure. This approach is deserved to be applied generally for providing a quite large operative field,making total tumor removal easier, and decreasing the incidence of postoperative complications. Key words: Transcallosal-interforniceal approach; Anatomy, regional; Microsurgery