Microsurgical Anatomy Of Transcallosal-interfornical Approach For Resction Of Tumor In The Ventricle And Its Clinical Application

Objective:To study microsurgical anatomy of transcallosal-interfornical approach for resction of tumors in the ventricle,in order to improve the curative effect and reduce the complications.Methods:12adult cadaveric head and6patients with tumors in the ventricale were studied. According to the horizontal line of the crown vector point and external auditory canal, a supine head is fixed in the frame. The microsurgical procession were imitated. The anatomic marks observed under microscope included:(1) the distribution and quantity of draining vein(frontal vein) and the bridging veins;(2)the structure of the inner cerebrum;(3)distribution and branch and diameter and variability of pericallosal artery;the blood supply of the corpus callosum;(4)structure of the septum pellucidum;the position of fornix and intermediate block;the roof of the third ventricle;the position of intermediate block;The measurement included:(1)the distance between nasal root and crown vector point;(2) the distance between the cerebral side margin (P5,P7)to the callosal sulcus;(3) the corpus callosum height;(4) the distance between the lower edge of the corpus callosum and the dome;(5) corpus callosum’s thickness;(6) the distance between the corpus callosum rim and interventricular foramen;(7) the distance between the corpus callosum under the surface of the point of intersection and the dome on the edge of the corpus callosum embedded wiring distance;(8) the distance between the corpus callosum under the surface of the intersection point and the corpus callosum the inner surface of the front knee point;(9) the distance between anterior commissure and the foramen of Monro on edge;(10) the distance between anteroposterior diameter of the thalamus intermediate block section, the upper and lower diameter,the distance between the thalamus intermediate block section and anterior commissure and post commissure.Results:1.The location of crown vector point is relatively fixed,the distance between coronal suture on the median sagittal line and nasal root is128.3±3.87cm,the former ranging frons1cm-4cm, no frontal veins in92%cadaveric head, and bridging veins sparse.2The tiny ateries on the corpus callosum of the central longitudinal grooves is served as a sign.There are a potential space of transparent septum in two leaves,the expansion of the potential space is known as the transparent compartment cavity or the fifth ventricle,the presence of the septum pellucidum gap in11cases, the separation from the septum pellucidum two leaves is easily,but is more difficult in1case.3Acorrding to reference point located in the cerebral hemisphere in flank the central sulcus before5cm and7cm points (P5,P7), the correlatve measurements obtained are as follows:(1) The distance between the cerebral side margin to the callosal sulcus are respectively38.64±3.59mm、37.39±2.98mm;(2) the corpus callosum height is6.71±1.50mm、7.15±1.26mm;(3) The distance between the lower edge of the corpus callosum and the dome is8.45±2.60mm、10.18±1.69mm;(4) Corpus callosum’s thickness is4.06±0.55mm、5.13±0.68cm;(5)The distance between the corpus callosum rim and interventricular foramen is15.62±2.83mm,15.68±1.80mm;(6) The distance between the corpus callosum under the surface of the point of intersection and the dome on the edge of the corpus callosum embedded wiring distance is12.84±2.09mm,18.46±2.70mm;(7)The distance between the corpus callosum under the surface of the intersection point and the corpus callosum the inner surface of the front knee point is21.04±2.95mm,14.84±3.1mm;(8)The distance between anterior commissure and the foramen of Monro on edge is5.03±0.80mm;(9) The distance between anteroposterior diameter of the thalamus intermediate block section is5.75±0.78mm,the upper and lower diameter5.23±0.89mm;the distance between the thalamus intermediate block section and anterior commissure is9.62±1.37mm,post commissure15.49±1.85mm.4. There are6patients with tumor in the third ventricle:total resection in4cases,subtotal resection in1case, partial resection in1case.postoperative fever in1case,diabetes insipidus in1cases, the patient’s clinical symptoms were improved.Pathological diagnosis:4ependymoma in4cases,glioma in1case,craniopharyngioma in1case.2cases are followed for3months in1case and after6months in1case and no tumor recurrence was discoveried.Conclusion:The transcallosal-interfornical approach to the three ventricle have a direct path and minimally damage to normal tissures for the microsurgical resection of tumors in the third ventricle.