Microsurgical anatomy from atrial portion of choroid fissure to quadrigeminal cistern

doi:10.3969/j.issn.1002-7386.2015.06.008

Abstract：Objective To study the anatomic features from atrial portion of choroid fissure to quadrigeminal cistern in order to provide an anatomic evidence for treating pathological changes around quadrigeminal cistern via choroidal approach in surgery.Methods Ten normal adult cadaveric heads (20 sides) fixed with 10%formaldehyde were enrolled in the study.The neurovascular structures around atrial portion of choroid fissure were observed,then the simulated surgical approach from atrial portion of choroid fissure to quadrigeminal cistern was performed under microscope.Results The atrial portion of choroid fissure was a strip of natural fissure that located between fimbria fornicis and pulvinar,in the medial wall of atrial portion of lateral ventricle.The pulvinar was posterior border of atrial portion of the fissure.The distance from pulvinar to trailing edge of trigone of lateral ventricles and central line was (15.9 ±3.3) mm and (21.6 ±2.8)mm,respectively.Moreover,the length of the fissure from pulvinar to the starting point locating behind foramen of monro was (31.4 ±3.5) mm.The quadrigeminal cistern could be accessed through choroid fissure in atrial portion.The anterior medial wall of the cistern was pineal body and quadrigeminum,and the distance from posterior border of the fissure to pineal body was (10.8 ±2.1) mm.The lateral posterior choroidal artery distributed to the choroid plexus locating in temporal horn,atrial portion and body portion of lateral ventricle via choroid fissure.The medial posterior choroidal artery distributed to the choroid plexus locating in interpositum of hanging wall of the third ventricle via quadrigeminal cistern.The medial atrial vein was a group of veins locating in the medial wall of atrial portion and occipital horn of lateral ventricle.This group of veins aggregated in choroid fissure and entered into internal cerebral vein or Galen's vein in quadrigeminal cistern via medial portion of fornix to form a simulated transchoroidal approach, with exposure range including quadrigeminal cistern and posterior part of ipsilateral ambient cistern.The most of blood vessels passing through quadrigeminal cistern could be well exposed, including P2 and P3 segment of posterior cerebral artery and basilar vein.The pineal body could be exposed after removing these blood vessels,however,the superior and inferior colliculus were difficult to be seen.Conclusion The neurovascular structures are complicated in atrial portion of choroid fissure and quadrigeminal cistern, so it is quite important to have an intimate knowledge for the related anatomical structures, and transchoroidal approach provides an natural pathway to treat the lesions around quadrigeminal cistern.